Front-section structure of a motor vehicle

For the reinforcement of a front section of a motor vehicle, a transverse beam is arranged between longitudinal beams of the body structure at the front side. The transverse beam is situated above the longitudinal beams and is adjoined by in each case one lattice girder. Each lattice girder extends in the longitudinal direction of the longitudinal beams and is connected at one side to the transverse beam and at the other side to a suspension unit mount.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority under 35 USC 119 to German Patent Appl. No. 10 2011 056 737.2 filed on Dec. 21, 2011, the entire disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a front-section structure of a motor vehicle.

2. Description of the Related Art

US 2008/0079290 A1 discloses a front section of a motor vehicle having a transversely situated frame part that is adjoined to the longitudinal sides of the vehicle by a structural element. The structural element is aligned vertically and comprises a lattice of vertical and horizontal webs that are connected to one another. DE 60 2004 008 372 T2 discloses a fender carrier for a motor vehicle. The fender carrier has ribs and webs that form an energy-absorbing structure.

It is an object of the invention to provide a front section for a motor vehicle. The front section should be connected to a reinforcement structure that acts in the longitudinal, transverse and vertical directions, and that has a suspension unit mount integrated therein.

SUMMARY OF THE INVENTION

The invention provides a front-end transverse beam and an adjoining lattice-like longitudinal beam that includes a suspension unit mount and that creates a front reinforcement structure in the front section. More particularly, a transverse beam is connected the front free ends of the longitudinal beams of the vehicle and is situated above the longitudinal beams. Lattice girders extend in the longitudinal direction of the longitudinal beams and are connected at one side to the transverse beam and at the other side to the suspension unit mount. The transverse beam connected to the lattice-like longitudinal beams and the suspension unit mounts provides a stable strength bond of the front section of the vehicle.

The transverse beam preferably comprises a transverse bar and two vertical transverse struts that are arranged below. The transverse struts extend at an angle from a vehicle longitudinal central axis to the longitudinal beams and are connected to vertical pillars that are fastened to the transverse bar of the transverse beam. The transverse struts provide additional stiffening of the transverse bar and significantly increase the transverse stability of the front section.

The lattice girder preferably is arranged in an approximately horizontal oblique plane between the bracket of the suspension unit mount and the transverse beam. The lattice girder preferably comprises two outer struts that diverge toward the bracket of the suspension unit mount and that have inner struts inclined at an angle with respect to the outer struts. An end-side inner strut runs from an outer strut to the transverse beam and is connected to the transverse beam, or the outer strut is connected directly to the transverse beam. The outer struts of the lattice girder preferably are screwed to the bracket of the suspension unit mount. The struts may be aluminum, CFRP or plastic.

The bracket for the suspension mount comprises two substantially vertical support arms. The suspension unit mount is arranged between the vertical support arms in a support plate, and the front support arm, as viewed in the direction of travel, is connected to the lattice girder. A support rod is connected to the support plate of each suspension unit mount and is inclined at an angle. A free end of the support rod is fastened to a cowl frame reinforcement. The support rods are connected to one another in a reinforcing manner by parallel transverse beams that have interposed webs.

A lattice-like suspension dome brace preferably is connected to the support plate by a circular plate, and the suspension dome brace is held with an opposite free end on the vehicle body. The arrangement of the suspension unit mount between the lattice girder and the suspension dome brace and the presence of the support rod achieve a stable arrangement of the suspension unit mount, and also reinforces the front section.

The longitudinal beams of the front section are provided with a fork at rear ends as viewed in the direction of travel. An upper longitudinal beam portion of the fork is connected to a bulkhead of the vehicle and a lower longitudinal beam portion of the fork is connected to an underfloor of the vehicle body. The fork of the ends of the longitudinal beam distribute forces to the bulkhead transverse beam of the vehicle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A front-section structure1of a motor vehicle comprises two longitudinal beams2,3that are connected to a bulkhead4and to an underfloor5of the vehicle body. A transverse beam6is connected to the front free ends of the longitudinal beams2,3of the vehicle and is arranged above the longitudinal beams2,3. Lattice girders7extend in the vehicle longitudinal direction at a distance from the longitudinal beams2,3. Each lattice girder7has a front end8, as viewed in the direction of travel F, connected with the transverse beam6and a rear end connected to a suspension unit mount9. One end of the suspension unit mount9on each vehicle side is supported on a suspension dome brace10and on a support rod11,11a. The support rods11,11aextend from the suspension unit mount9in the direction of the bulkhead4or a cowl frame12of the vehicle body and support the suspension unit mount9.

The transverse beam6comprises a transverse bar6aand two transverse struts14,15. The transverse struts14,15are below the transverse bar6aand extend at an angle from the vehicle longitudinal central axis L to the longitudinal beams2,3and are fastened to the longitudinal beams2. The transverse bar6ais connected to the transverse beams2,3via vertical pillars17,18that are supported on the transverse struts14,15.

The lattice girders7extend obliquely between the suspension unit mount9and the transverse beam6in an approximately horizontal plane above the longitudinal beam2,3.

Each lattice girder7extends between two outer struts19,20that diverge toward the bracket9aof the suspension unit mount9. Inner struts21,22,23or23aare arranged between the outer struts19,20of each lattice girder7and are inclined at an angle. The end-side inner strut23amay extend from the outer strut19to the transverse bar6aof the transverse beam6and may have an end connected to the transverse bar6a, as shown in more detail inFIG. 1. In a further possible embodiment, the ends of the outer struts19,20are connected directly to the transverse bar6aand the end-side inner strut23ais arranged between the outer struts19,20, as shown in more detail inFIG. 2.

The bracket9afor each suspension unit mount9has two vertical support arms24,25and the suspension unit mount9is arranged in a support plate26between the support arms24,25. The lattice girder7is connected, for example, by a screw connection to the support arm25, which is situated at the front as viewed in the direction of travel F. Feet A of the support arms24,25are fastened to the longitudinal beam2,3.

Horizontal support rods11,11aare connected to the support plates26of the suspension unit mounts9at each side of the vehicle and are oriented at an angle with to the vehicle longitudinal central axis L. Free ends of the support rods11,11aare fastened to the cowl frame12. The support rods11,11aalso are connected in a reinforcing manner by at least two parallel transverse bars28,29. Struts28a,29aare arranged between the two transverse bars28,29and are inclined at an angle.

Each suspension dome brace10is connected to the support plate26by a circular plate30. The opposite free ends of each suspension dome brace10is held on the vehicle body. The suspension dome brace10preferably is formed with a lattice structure composed of webs10aarranged in zig-zag configuration between the inner and outer walls of the suspension dome brace10.

The support arms24,25of the bracket9aof the suspension unit mount9are connected via the feet A directly to the longitudinal beams2,3. The longitudinal beams2,3have a fork31at the rear as viewed in the direction of travel F. An upper longitudinal beam portion32of the fork31is connected to the bulkhead4of the vehicle, and a lower longitudinal beam portion33of the fork31is connected to the underfloor5of the vehicle body, such that a distribution of forces is realized by the fork31of the longitudinal beams2,3, as shown inFIG. 3by the arrows P and P1. A lateral continuous profile element36is provided on the underfloor5and is arranged on the lower edge of the tunnel to adjoin the longitudinal beams2,3. The profile element36reinforces a central tunnel35of the vehicle.