Disclosure of Invention
The object of the invention is to show a measure which makes it possible to at least reduce the perceived driving noise in the passenger compartment of a motor vehicle.
According to the invention, this object is achieved by a rear parcel shelf arrangement having the features described below. Preferred refinements of the invention are specified in the following description, which may in each case constitute an aspect of the invention individually or in combination.
According to the present invention, there is provided a rear package shelf arrangement for covering a trunk of a motor vehicle, the arrangement having: a pivotally mounted lower structure for covering the trunk in a closed position; a rear parcel shelf placed on the substructure for covering the substructure, wherein the rear parcel shelf has a cover extension (Abdeckansatz) which faces the seat back and a main portion extends in a vertical direction; and an elastically deformable elastic body arranged between the cover extension and the lower structure, wherein the cover extension is configured to be bendable by the elastic body so as to press the cover extension against the seat back in the closed position.
A wheel house for accommodating the rear wheels may be provided in a trunk of the motor vehicle, and thus rolling noise of the rear wheels and/or structural noise of the wheel house, which is caused by vibration of the rear wheel shaft, may be transmitted into the trunk. However, in order to be able to pivot the rear package shelf arrangement in order to open the trunk, a gap is required between the rear package shelf and the rear side of the seat back so that the rear package shelf arrangement is not obstructed and/or blocked during pivoting. It is basically possible for the sound transmitted into the trunk to enter the passenger compartment of the motor vehicle via the gap and to make the passengers feel unpleasant noise disturbances. In particular when the motor vehicle is permanently or at least temporarily electrically driven, the acoustic masking of the internal combustion engine noise is absent, so that the sound entering the passenger compartment via the trunk can be perceived in particular.
By providing an elastic body between the cover extension and the substructure, the cover extension can be pressed against the seat back by the elastic body, so that a gap between the rear package shelf and the rear side of the seat back, which gap is provided for the pivoting of the rear package shelf arrangement, can be closed. The following findings were utilized in this regard: the rear package shelf is produced from a softer material (for example with a textile part), while the substructure is produced from a harder material (in particular a metallic material or a thermoplastic material) than the rear package shelf. This makes it possible to apply a sufficiently large elastic force to the cover extension by the elastic body so as to cause the cover extension of the rear parcel shelf to leave the neutral starting position to elastically bend until the cover extension abuts against the seat back. Thus, the gap provided between the rear package shelf arrangement and the seat back may be acoustically sealed, and therefore sound propagating into the trunk may (if at all) enter the passenger compartment only in a significantly attenuated form.
In the region of the rear parcel shelf and the substructure which in the closed position extends mainly horizontally, two layers are already present with the rear parcel shelf and the substructure, which layers have in particular a substantially completely closed design and between which a cavity is preferably formed at least in partial regions. The two layers and optionally the cavity provided may already have a sound-absorbing effect and may form an acoustic damping which may prevent or at least attenuate sound coming out of the boot from passing through these areas into the passenger compartment. However, in the region of the gap formed between the rear package shelf and the seat back, sound can then pass through the substructure, and therefore the substructure in this region is not an acoustic damping element that absorbs sound. The elastomer may cover the cover extension to such an extent that the elastomer may also function as an acoustic damping element that absorbs sound, so that the elastomer may, together with the cover extension, achieve a sufficient acoustic seal for the gap formed between the rear package shelf and the rear side of the seat back. Due to the dimensionally elastic design of the elastomer body, manufacturing and positional tolerances between the seat back and the cover extension can be easily compensated for, and thus good sound damping can be obtained at low production costs. By means of the cover extension of the rear parcel shelf which is pressed against the seat back by means of the elastically deformable elastomer, an acoustic sealing of the trunk is achieved, so that the driving noise which can be felt in the passenger compartment of the motor vehicle can be at least reduced.
In particular, in the closed position, the elastomer is under prestress. Thus, the elastic body can act on the cover extension with a certain minimum elastic force. It is thus possible for the cover extension to remain in abutment against the rear side of the seat back and not be lifted off even in the event of a sudden impact (for example when the vehicle drives over a pothole).
The elastomer is preferably fastened to the cover extension and/or to the substructure. The elastomer can be supported on the respective other component when the elastomer is fastened only to the cover extension or only to the substructure. When the cover extension is laterally offset with respect to the substructure, shear loading of the elastomer can be avoided, so that the loading of the elastomer can be kept small. When the elastic body is fastened to the cover extension and to the lower structure, the downwardly protruding cover extension may be held by the elastic body on the lower structure during opening of the trunk by pivoting the rear package shelf arrangement, thus avoiding splaying. Thus, for example, it is possible to avoid: when the trunk is loaded, a portion of the load enters the gap opening between the cover extension and the substructure and affects the operational functioning of the rear parcel shelf arrangement during pivoting.
Particularly preferably, the cover extension is positioned at a distance from the seat back so as to form a gap, with the smallest possible extension of the elastomer between the cover extension and the substructure. And if the elastomer is maximally compressed or absent when the rear package shelf arrangement is in the closed position, a gap will be formed between the cover extension and the seat back. A gap is intentionally formed when the cover extension is in an unbent unstressed, unstressed base position. Only the elastic force applied by the elastic body can bring the cover extension into contact with the seat back. Thus, in the closed position, good sound insulation is provided, while ensuring that the cover extension is slightly bent during pivoting of the rear parcel shelf arrangement. It is thereby avoided that the pivoting movement of the rear package shelf arrangement is blocked by the friction force exerted by the cover extension on the seat back.
The pivot axis of the substructure extends in particular at a distance from the cover extension. The elastomer can compensate for the moving parts of the cover extension which occur during the pivoting movement of the rear package shelf arrangement about the pivot axis in the longitudinal direction of the motor vehicle (corresponding to the direction of travel) towards and/or away from the seat back. Therefore, the pivot shaft does not have to be disposed as close to the seat back as possible. Instead, the pivot axis may be arranged significantly spaced from the seat back, thus obtaining an additional structural freedom of the kinematics of movement of the rear package shelf arrangement during opening and closing of the trunk.
The elastomer is preferably produced from a foam, in particular from polyurethane. The foam may in particular be formed from a cured foam. Sufficient compressibility is obtained by pores or cavities provided in the foam, so that the foam can be elastically deformed. At the same time, it is possible to produce sponge-like foams from thermosetting plastics, so that the elastomers can have good elastic properties and high permanence.
Particularly preferably, the elastomer and/or the cover extension are distributed over substantially the entire width of the side of the rear parcel shelf facing the seat back. Thus, the cover extension may be pressed against the seat back by a substantially constant spring force over the width of the vehicle. Inadequate sealing of the local area where noise can enter from the trunk into the passenger compartment is thus avoided.
In particular a loudspeaker for emitting audible sound is fastened to the substructure. The loudspeaker may for example be part of an entertainment system in order to fill the cabin with music. In principle, the loudspeaker (especially at high volumes) is capable of generating vibrations that excite the substructure, thereby emitting annoying structural noise. This type of structure noise may be perceived as an uncomfortable buzz. But in the closed state of the rear parcel shelf arrangement the elastomer presses not only against the lid extension but also against the substructure. The elastomer can thus attenuate substructure vibrations which lead to structure noise, and undesired noise can be avoided or at least attenuated despite the excitation of the substructure by the loudspeaker.
Preferably, a damping material is provided between the substructure and the rear package shelf for compensating for a change in the distance of the rear package shelf relative to the substructure when the trunk lid strikes said rear package shelf, wherein the damping material is guided in particular through a through-going slot formed between the substructure and the rear package shelf for damping noise striking the trunk lid. The damping material may dampen the shock when the trunk lid strikes the rear package shelf arrangement during closing of the trunk lid. At the same time, the damping material disposed between the rear package shelf and the substructure also provides additional sound attenuation.
The invention also relates to a motor vehicle rear part for a motor vehicle, having: a trunk, a seat back bounding the trunk in the direction of travel, and a pivotable rear parcel shelf arrangement bounding the trunk upwardly in the closed position, which may be designed and improved as described above. By the cover extension of the rear parcel shelf which is pressed against the seat back by means of the elastically deformable elastomer, the effect of acoustically sealing the trunk is achieved, so that the driving noise which can be felt in the passenger compartment of the motor vehicle can be at least reduced.