WO2004104442A1

WO2004104442A1 - Damping strut for stabilizing body parts, and vehicle body comprising damping struts

Info

Publication number: WO2004104442A1
Application number: PCT/EP2004/005110
Authority: WO
Inventors: Wolfgang BÖHNKE; Philippe Verdun
Original assignee: Daimlerchrysler Ag
Priority date: 2003-05-24
Filing date: 2004-05-13
Publication date: 2004-12-02
Also published as: DE10323724A1

Abstract

Disclosed are a damping strut (1) for stabilizing parts of a body, especially a vehicle body, and such a vehicle body. Said damping strut (1) comprises at least two fastening points (3, 4) and two separate strut parts (5, 6) that are located between the fastening points (3, 4). The strut parts (5, 6) are connected to each other by means of an intermediate layer (8) made of a viscous, elastically deformable material.

Description

Damping strut for stabilizing body parts and motor vehicle body with damping struts

The invention relates to a damping strut for stabilizing parts of a body, in particular a vehicle body of a convertible, according to the features of the preamble of claim 1 and a vehicle body with damping struts according to the features of the preamble of claim 9.

The problem with modern car bodies for motor vehicles, in particular with car bodies of convertibles or roadster vehicles, is that the lack of a closed roof construction means that the various parts of the car body are not sufficiently stable against deformation. In the case of convertible vehicles in particular, the body can twist about a longitudinal axis of the vehicle (torsional deformations), which can lead to problems with other components, such as the vehicle's windshield. For this purpose strut components are known which are additionally installed in areas of the vehicle body which are critical to deformation. For example, in the case of convertibles, pairs of stiffening struts running crosswise or diagonally are installed in the floor area, which prevent the body from twisting due to the additional stiffening by means of the struts.

From German patent DE 39 05 650 Cl, for example, diagonally arranged struts for stiffening a ner body known. The stiffening struts are aligned diagonally to a longitudinal axis of the vehicle on the underside of a base plate and fastened between side longitudinal members and a central region of the floor of the body. The problem here is that despite these stiffeners, vibration problems still occur, which lead to a phenomenon called "vehicle shaking". This is extremely uncomfortable for the occupants. Additional vibration dampers of conventional design are therefore usually used to improve comfort. Such vibration absorbers, also known as mass absorbers, counteract the vibration vibrations that occur by means of a specific mass with a counterforce that contributes to damping the vibrations. The disadvantage here is that the additional vibration absorbers are complex to manufacture and difficult to accommodate in existing bodies. In addition, such vibration dampers lead to a not inconsiderable increase in the overall weight of the vehicle.

Another system for stabilizing body parts is known from German Offenlegungsschrift DE 198 20 617 AI. To stabilize the body of a convertible vehicle, diagonally arranged stiffening struts are provided, which are variable in length. The diagonal struts have a receiving unit for recording a longitudinal load, an actuator for causing a counterforce and a control unit for the actuator. In this way, a corresponding counterforce can be introduced into the damping struts of the device by the actuator in the manner of active damping in accordance with the oscillations or vibrations occurring in the body. The disadvantage here is the considerable additional manufacturing effort. On the other hand, the damping strut of this known system must be wired to a controller. The cost of such active damping is considerable. Last but not least, such a damping strut for stabilizing vehicle parts creates problems. obviously installation if only a small space is available.

The present invention has for its object to provide a damping strut for stabilizing body parts of a vehicle and a vehicle body with damping struts, which allow a structurally simple way to stabilize body areas with simultaneous damping of vibrations generated thereby.

This object is achieved by a damping strut with the features of claim 1 and with a motor vehicle body with the features of claim 9. Advantageous refinements and developments of the invention are specified in the dependent claims.

The damping strut according to the invention for stabilizing parts of a vehicle body with the features of claim 1 has at least two fastening points and at least two separate strut parts between these fastening points. The strut parts are firmly connected to one another by means of an intermediate layer made of a viscous, elastically deformable material. The separate parts of the strut are preferably only connected to one another by the flat intermediate layer, which is made of a specific material that allows absorption of tensile and compressive stresses and their compensation by material deformation. The vibration or vibration forces that occur can be effectively compensated for in a structurally very simple manner by this material deformation in the viscous intermediate layer. The tensile and compressive forces that occur on the damping strut are converted into shear forces in the intermediate layer made of viscous, elastically deformable material and thus lead to an energy conversion. This damping effect does not require complex equipment and changes in existing designs. The damping strut according to the invention is little takes up space and can also be used in environments that are exposed to external environmental influences, in particular dirt and damage. The damping strut is simply attached to the parts of the body to be dampened and stabilized, for example by means of fastening screws, using two fastening points. The relative, low mobility between the parts of the strut is ensured by the viscous, elastically deformable intermediate layer between these parts. The strength of the damping of vibrations occurring and the frequency range of dampable vibrations are preferably achieved by a selection of a suitable material and / or a material thickness of the intermediate layer between the flat sections of the struts.

According to an advantageous embodiment of the invention, the intermediate layer is formed from a material such that a vibration-induced tensile and compressive stress on the damping strut can be largely compensated for by a slight deformation of the material of the intermediate layer. A specific choice of material for the intermediate layer, which is therefore suitable for the application, can largely prevent any resonance between the parts of a body to which the damping strut is connected. A "transverse shaking" or "shaking", as can often occur in convertible vehicles, can be effectively avoided in this way. At the same time, the rigidity required for good vehicle behavior is nevertheless guaranteed. The material of the intermediate layer is preferably selected from materials which have a relatively high viscosity and are in particular easily elastically deformable. The material selection of the intermediate layer is carried out according to the respective specific requirements of the stabilizing and damping effect of the strut. In particular, elastic plastic, such as elastomers or rubber materials, can be used to implement the strut according to the invention. The corresponding deformable speed of the material is selected in connection with the thickness of the intermediate layer, which is essentially relatively thin, such that the most frequently occurring vibrations or oscillations can be damped. Nevertheless, effective stabilization or stiffening of body parts is possible with the damping strut according to the invention. The greater the viscosity of the material used for the intermediate layer, the thinner it can be. The intermediate layer is preferably not thicker than on the order of a few millimeters.

According to an advantageous embodiment of the invention, the parts of the damping strut are connected to the intermediate layer by adhesion. The adhesive effect is achieved, for example, by a direct fusion of the strut parts with the intermediate layer or by overmolding with an appropriately adapted plastic material as the material of the intermediate layer. The direct liability ensures that a movement of the parts beyond a minimum relative movement of the strut parts to one another is reliably avoided, so that sufficient rigidity and stability in the body areas of the vehicle is ensured. The slight displacement or relative movement of the parts to one another due to a deformation in the material of the intermediate layer allows the thrust and tensile forces that occur to be largely damped, since this absorbs the kinetic energy.

According to an advantageous, alternative embodiment of the invention in this regard, the strut parts of the damping strut are connected to one another by gluing to the intermediate layer. The manufacture of the damping strut according to the invention is facilitated since it is not necessary to pour over the intermediate layer together with the parts of the strut. The intermediate layer can be produced separately and can be attached to the respective parts of the damping strut by simply gluing or gluing. The bond is preferably such that a high level of adhesion is ensured a long period of time. As a result, the tensile and compressive stresses of the strut are completely introduced into the material of the intermediate layer, and there is no damage or malfunction of the mode of operation. An additional or alternative anchoring of the material of the intermediate layers on the strut parts can also take place via several recesses into which material projections of the intermediate layer engage or are cast.

According to an advantageous embodiment of the invention, the strut parts are flat-bar-shaped, with two outer strut parts receiving an inner strut part between them, each with an intermediate layer on the abutting sections of the strut parts. As a result, the damping strut according to the invention can be made relatively flat and nevertheless has effective damping of the vibrations which are harmful to comfort in the respective frequency range. The damping strut can also be mounted, for example, on the underside of a base plate of a body of a vehicle, since it is designed to be relatively flat. The design of the strut parts in the form of flat rod parts also makes it possible to apply a sufficiently large, flat intermediate layer with a viscous, elastic material to the wide long sides of the flat rods. As a result, the damping effect according to the invention is nevertheless ensured with a relatively thin layer.

According to an advantageous embodiment of the invention in this regard, a plurality of layers of respective inner strut parts with outer strut parts and corresponding intermediate layers are provided. The multilayer structure has the advantage that the damping effect of the intermediate layers can be increased as a result if necessary. This is achieved by a plurality of layer assemblies from inside and outside, flat bar-shaped strut parts, between each of which an intermediate layer firmly connected to them is provided. The proportion of the intermediate layers with the vis- This increases the elastic, deformable material. The damping factor can thus be varied over a wide range.

According to a further advantageous embodiment of the invention, the strut parts are tubular or rod-shaped, an inner tube or a rod being telescopically inserted into an outer tube and fastened via an annular intermediate layer. The strut parts can be made from a conventional tubular profile or rod profile and are preferably matched to one another in their diameters such that the intermediate layer made of a viscous, elastically deformable material has a predetermined thickness between the telescopically inserted parts. The attachment points can be realized, for example, by means of welded-on tabs with attachment holes or in some other way. The design of the damping strut according to the invention as a telescopic tube element has the advantage that a relatively large area and thus a large damping effect can be achieved in a small space. The flat intermediate layer, which is responsible for the damping, is arranged in a ring on the inside of the outer tube and on the outside of the inner tube or the rod and accordingly does not require a wide configuration in the form of a flat rod-shaped strut part.

The vehicle body according to the invention according to the features of claim 9 is in particular a self-supporting motor vehicle body of a convertible or a roadster and has a floor and cross members and longitudinal members, at least one damping strut according to the invention being provided for vibration-damping stiffening of the body. The stiffened parts of a body can, for example, be the base plate itself, which is stiffened against torsional deformations. The body areas, which are equipped with damping struts according to the invention, can also be transverse areas between the longitudinal and transverse beams, for example in the area between the windshield cross member and the cockpit of a passenger compartment. According to the respective requirements, the damping strut according to the invention can be mounted on the body alone or in combination with conventional, undamped stiffening struts. The damping strut according to the invention is preferably used in the vibration-sensitive areas and is screwed to the vehicle body via its fastening points. Body areas can thus be stiffened sufficiently without causing an unpleasant "body shake".

According to an advantageous embodiment of the invention, damping struts running diagonally in relation to the longitudinal axis of the vehicle are provided on the floor of the motor vehicle body between the longitudinal members and a central, central region of the floor for torsion stiffening. The damping struts are preferably arranged at an angle of approximately 45 ° in relation to the longitudinal axis of the vehicle. The damping struts are preferably arranged in pairs in the form of a "V", but they can also be arranged in the form of an "X" or fastened to the floor of the motor vehicle body. This results in an improved stiffness of the vehicle body as a whole, the chatter, such as vibrations, which normally occur in convertible bodies with undamped stiffening, being effectively avoided. The driving comfort of the vehicle is improved. The driving behavior and road holding are still guaranteed.

According to an advantageous embodiment of the invention, damping struts according to the invention are arranged crosswise and arranged transversely to the longitudinal axis of the vehicle between the floor of the body and a cross member. The cross-shaped stiffening has the advantage that tensile and compressive stresses can be effectively absorbed and damped or stiffened on both sides. The arrangement of cross-shaped damping struts according to the invention can, for example, the cockpit area between a cross member of the bottom plate of the body and a windshield support are firmly mounted. However, the crosswise arrangement of two damping struts according to the invention can alternatively or additionally be arranged in a rear area of the motor vehicle, for example between the rear upper cross member below the rear shelf and a lower cross member or the base plate directly.

Further advantages and features of the invention can be found in the following detailed description, in which the invention is described in more detail with reference to the exemplary embodiments illustrated in the accompanying drawings.

The drawing shows:

Figures la and lb are a sectional side view and a plan view of a first exemplary embodiment of a damping strut according to the invention;

2 shows a sectional side view of a second exemplary embodiment of a damping strut according to the present invention;

3 shows a schematic plan view from below of an exemplary embodiment of a motor vehicle body with damping struts according to the present invention;

4 and 5 are schematic views of exemplary embodiments of an arrangement of damping struts in a vehicle body between transverse and longitudinal beams according to the present invention. FIGS. 1 a and 1 b show a first exemplary embodiment of a damping strut according to the present invention in a sectional side view and a top view. The damping strut 1 of this embodiment consists of an inner strut part 5 and two outer strut parts 6, 7, which enclose the inner strut part 5 between them. The outer strut parts 6, 7 and the inner strut part 5 are each firmly connected to one another via an intermediate layer 8 made of a viscous, elastically deformable material. The outer strut parts 6, 7 and the inner strut part 5 are each connected to one another only via a relatively thin layer of a viscous material through the applied intermediate layers 8. As a result, shear and tensile loads at the fastening points 3, 4 in the strut can be absorbed by a slight deformation of the thin intermediate layer 8 made of viscous, elastically deformable material: the material of the intermediate layer 8 is viscous and elastically deformable, as a result of which a slight relative shift in the longitudinal direction of the Strut 1 between the outer strut parts 6, 7 and the inner strut part 5 is made possible. In the event of a stress at the fastening points 3, 4 to the vehicle body (not shown), energy from the stresses of the strut 1 can thus be absorbed in the intermediate layer 8. The occurrence of vibrations due to the stiffening of body parts by the strut 1 can thereby be avoided in a simple manner. Active damping systems, which are structurally complex, are avoided, as are additional damping devices on the body, such as mass silencers.

The dimensions of the damping strut according to the invention are hardly increased compared to conventional, undamped stiffening struts. Installation on existing vehicle bodies is made possible without conversion. In the exemplary embodiment in FIGS. 1 a and 1 b, the outer strut parts 6, 7 are connected to one another by a spacer part 14 at the fastening point 3. The strut parts 6, 7 can be welded to the spacer part 14. The fastening points 3, 4 are realized as screw holes in the exemplary embodiment. An essential aspect of the present invention is that the connection between the inner 5 and the outer 6, 7 strut parts only takes place through the material-specific intermediate layer 8. In this way, vibrations that occur due to the stiffening of a vehicle body can be largely compensated for by selecting a suitable damping material for the intermediate layer 8. The intermediate layer 8 is, for example, made of a plastic material, such as an elastomer with high toughness. The connection of the intermediate layer 8 with the strut parts 5, 6, 7 takes place either directly by spraying on the material of the intermediate layer 8 or in another way known to the person skilled in the art, such as for example by gluing to the longitudinal surfaces of the strut parts 5, 6, 7.

As an alternative to the illustrated embodiment, the damping strut 1 according to the invention can also be formed from a plurality of layers of inner strut parts 5 and outer strut parts 6, 7. The strut parts 5, 6, 7 can accordingly be made thinner, as a result of which the relative proportion of the material of the intermediate layer is increased. The strut parts can alternatively also have a profiled shape. For example, the outer strut parts 6, 7 can be L-shaped or at least one U-shaped, which enables lateral protection of the intermediate layer.

2 is a sectional side view of a second embodiment of a damper according to the invention played strut. The damping strut 1 of the second exemplary embodiment consists of a tube or rod part 9 as an inner strut part, which is inserted into an outer tube 10 with a diameter and is fastened by means of a flat intermediate layer 8 according to the invention. The intermediate layer 8 made of viscous material is thus a continuous, cylindrical material layer, which is preferably introduced as a thin coating between the overlapping sections of the inner rod 9 and the outer tube 10. At the free ends of the strut parts 9, 10 fastening tabs 15 are attached by tapering the respective pipe parts 9, 10, in which holes 16 are provided for fastening screws at the fastening points 3, 4. The strut 1 can also be fastened to the body of a vehicle by other means known to the person skilled in the art for this purpose.

3 shows an embodiment of a vehicle body according to the invention with damping struts attached to the floor in a top view from below. The vehicle body 2 has on the underside of the vehicle floor 11 four damping struts 1 according to the invention, which in this exemplary embodiment correspond in structure to the damping strut according to FIGS. 1 a and 1 b. The damping struts 1 are thus relatively flat and can be attached to existing floors of vehicle bodies 2 without any design changes. The attachment is preferably carried out by means of screws at the attachment points 3 and 4. The arrangement of the damping struts 1 on the underside of the vehicle floor is provided in this embodiment to increase the torsional rigidity of the body 2. For this purpose, two damping struts 1 are provided in a V-shaped arrangement between a central central region of the base 11 and the lateral outer longitudinal member 13. seen. The diagonal or inclined arrangement of the struts 1 with respect to the longitudinal axis of the vehicle 2 avoids twisting of the vehicle floor under loads during driving, which can occur in particular in convertible vehicles, due to the lack of a closed roof structure. Nevertheless, this stiffening by means of the damping struts 1 of the vehicle floor 11 does not lead to the vehicle shaking or shaking as in previously known systems of stiffening. The structure of the damping struts 1 according to the invention is provided with a viscous, elastically deformable intermediate layer 8 between the strut parts. The material of the intermediate layer 8 is selected such that the most frequently occurring vibrations can be largely absorbed by the stiffening of the vehicle floor 11. This can be done with structurally simple measures, an improved stiffening of body parts. The disadvantageous vibrations are effectively avoided without additional effort. In particular, additional devices such as mass compensators or actively controlled damping units with corresponding electronic controls are not required.

4 and 5 schematically show two further exemplary embodiments of an arrangement of damping struts in a vehicle body. In these exemplary embodiments, two damping struts 1 according to the invention are arranged crosswise to one another. 4, two damping struts 1 are arranged between a front cross member 12, a tunnel 17 and a cockpit cross member 12 or windshield support. The fastening in the fastening points 3, 4 of the struts 1 also takes place here by means of a screw connection or a direct welding to the vehicle body 2. This stiffening arrangement of the damping struts 1 serves to increase the rigidity of the front Cockpit area of the vehicle body 2, without a significant increase in weight of the vehicle body 2.

5 shows a corresponding, cross-shaped arrangement of two damping struts 1 in the rear body region of a vehicle body 2. The damping struts 1 are fastened here between an upper cross member 12 (facing the parcel shelf) and a lower cross member 12 in the floor area 11 of the body. In this arrangement, the damping struts 1 can preferably have the form of tubular damping struts according to FIG. 2. Flat training is not required in these areas.

All of the features and elements represented in the description, the following claims and the drawing can be essential to the invention both individually and in any combination with one another.

Claims

claims

1.Damping strut (1) for stabilizing parts of a body, in particular a vehicle body (2), with at least two fastening points (3, 4) and at least two separate strut parts (5, 6, 7, 9, 10) between the fastening points (3 , 4), characterized in that the strut parts (5, 6, 7, 9, 10) are interconnected by means of an intermediate layer (8) made of a viscous, elastically deformable material.

2. Damping strut (1) according to claim 1, so that the intermediate layer (8) is formed from such a material that a vibration-induced tensile and / or compressive stress on the strut (1) can be largely compensated for by a slight deformation of the material.

3. Damping strut (1) according to claim 1 or 2, so that the strut parts (5, 6, 7, 9, 10) are connected to one another by adhesion to the intermediate layer (8).

4. Damping ungs strut (1) according to claim 1 or 2, characterized in that the strut parts (5, 6, 7, 9, 10) by gluing the intermediate layer (8) are connected to one another.

5. damping strut (1) according to any one of the preceding claims, characterized in that the strut parts (5, 6, 7) are flat bar-shaped and that two outer strut parts (6, 7) between them receive an inner strut part (5), each with an intermediate layer (8) on the adjacent sections of the rod-shaped strut parts (5, 6, 7).

6. Damping strut (1) according to claim 5, that a plurality of layers of a respective inner strut part (5) and outer strut parts (6, 7) with corresponding intermediate layers (8) are provided.

7. damping strut (1) according to any one of claims 1 to 4, characterized in that the strut parts (9, 10) are tubular or rod-shaped, an inner tube or a rod (9) telescopically inserted into an outer tube (10) and is fastened via an annular intermediate layer (8).

8. Damping strut (1) according to one of the preceding claims, that the intermediate layer (8) is formed from a layer or covering of an elastomeric plastic which is thin in relation to the material thickness of the strut parts (5, 6, 7, 9, 10).

9. Motor vehicle body (2), in particular self-supporting motor vehicle body of a convertible or a roadster, with a floor (11) and with cross members (12) and side members (13), characterized in that at least one damping strut (1) according to one of the previous claims 1 to 8 for vibration-damped stiffening of the body (2) is provided.

10. Motor vehicle body (2) according to claim 9, characterized in that on the floor (11) diagonally in relation to the vehicle longitudinal axis damping struts (1) between the side members (13) and a central, central region of the floor (11) for torsional stiffening are provided.

11. Motor vehicle body (2) according to claim 9 or 10, d a d u r c h g e k e n n z e i c h n e t that cross-arranged pairs of two damping struts (1) are provided transversely to the longitudinal axis of the vehicle between the floor area (11) and a cross member (12).