Load-bearing structure

The invention relates to a supporting structure is optionally fixed or mobile set.

According to the prior art device components that are selectively connected to each other rigidly or movably, connected by a hinge with a locking device can be locked or released, which, for example by a control unit operable. The known bearing Structures that selectively rigid or movable set are, that require complex joints and a locking device, Thus, a variety of components. This is particularly lightweight disadvantageous whose top The aim, of course, the weight reduction associated with a Reducing the number of components is.

The object of the invention is to provide a simply constructed light provide supporting structure either rigid or movable adjustable.

This is achieved according to the features specified in claim 1 achieved bearing structure. In the dependent claims are advantageous Embodiments of the invention shown.

According to the invention, the supporting structure at least partly from a thermoplastic material, the softening a above the operating temperature of the bearing having structure such that in the operating condition of the bearing Structure is rigid. The thermoplastic material is a heater to a temperature above its softening temperature be heated, whereby the rigid condition of the supporting structure eliminated, ie, the supporting structure movable can be adjusted. After cooling, to the Operating she takes again the rigid state on. According to the invention thus is a supporting structure with integrated release and locking function provided.

According to the invention so that the previous concept, the multi-part adjustable construction of either fixed or mobile bearing structures provides departed. The invention supporting structure is characterized by contrast by a function or from parts integration, by the switchable rigidity of the thermoplastic material is made possible. Moreover, required the invention supporting structure for the design change process only small Gillnet or deflection forces.

As used for the inventive transmitted structure thermoplastic material is preferably a thermoplastic Plastic. Here are higher melting thermoplastic Plastics such as polyetheretherketone (PEEK), or Polyether sulfone (PES), are generally preferred as they have a have relatively high softening temperature, and thus the Operation of the superstructure at a correspondingly high Temperature allow.

The inventive supporting structure can in different Way be constructed. They can, for example all of a thermoplastic material, ie a thermoplastic his material existing component.

However, the inventive supporting structure can also, for example, consist of two or more components which are connected by the thermoplastic material. The components then must have a softening, above the softening temperature of the thermoplastic Material is. For this purpose, the components of metal, especially a light metal or of a plastic, in particular fiber-reinforced plastics material having a higher Has softening temperature than the thermoplastic Material that connects the component or assembly.

If the supporting structure consists of components that are connected by the thermoplastic material, is thus a rigid connection of the components at operating temperature, ie below the softening temperature of the thermoplastic Material before, the rigid connection of the components by heating the thermoplastic material to Erweichungsemperatur be achieved by the heating device can.

Since the thermoplastic material to its softening in any way is deformable, the mobility of the supporting structure be designed very differently.

If the supporting structure, for example by the thermoplastic material connected components is, the thermoplastic material to its softening, be exposed, for example, a thrust load to the Components against each other to move, or a bending load, around the components to bend relative to each other, or a torsional load to the components mutually to twist. The softened thermoplastic material So therefore forms eg a sliding joint, flexure or Torsion.

In particular, in the lightweight construction so that there are a variety of applications for the inventive load-bearing structure, for example where a bending in operation or torsion Component changed operating conditions in its outer Geometry is adaptively adjust without spending costly joints or the need to provide mechanisms.

By softening of the thermoplastic material to the softening temperature order to enable the stiffness of the bearing Structure can be lowered if necessary to relatively low Force the structure to deform or the component parts to move against each other, before rising again to the rigidity by cooling the thermoplastic Material to a temperature below its softening temperature the deformed shape without permanent maintaining force or mutually shifted Components in turn can be locked together. This process is virtually as often reversible feasible.

The thermoplastic material may have any form. That is, for example, a plate, a Klotz, a film, a rod, for example, round or angular cross-section or other arbitrarily shaped his body.

According to one embodiment of the invention, the supporting Structure to a sandwich structure. That is, the thermoplastic Material forms a layer between two Layers of at the softening temperature of the thermoplastic Materials resistant material is arranged. This in solid softening temperature of the thermoplastic material Material may, for example a metal, especially a light metal or a plastic, in particular a fiber-reinforced plastic with correspondingly high softening or decomposition temperature be. The external or outer layers may be plate-shaped but formed in a different manner, for example consist of concentrically arranged tubes, between which the thermoplastic material is.

If exposed to such a sandwich structure of a bending load to be, the outer layers of a need made in accordance with flexible material. The outer layers are generally material-tight manner, in particular when the thermoplastic material to a plastic state is softened; However, they can also consist of a porous material, for example, expanded metal or the like. exist.

The heating device for heating the thermoplastic material the supporting structure of the invention, a be of electrical resistance heating, the thermoplastic in the having material embedded heating wires. The heating wires are designed in accordance with the load to which they are exposed when the supporting structure according to softening the thermoplastic material is moved. The heating wires can therefore, for example, spiral, zigzag or arranged serpentine in the thermoplastic material be.

Instead of an electrical resistance heater, the heater may be formed by a contact, convection, radio frequency or radiant heating. Using a high frequency heating a thermoplastic around the Material arranged high-frequency coil, the thermoplastic Material for example, of a polymer having respective dielectric properties exist and / or in the thermoplastic material can be metal or other electrically conductive particles can be embedded.

To the supporting structure from the rigid to the mobile State out, does not have the entire thermoplastic Material are heated to softening temperature. Much more can also only the inner portion of the thermoplastic material are heated to softening temperature, or an external outer edge zone of the thermoplastic material, or both, Marginal zones. Since in the heating of the inner portion the heat loss is less, however, in general, the Heating the inner region preferred. The radiation, Contact or convection heating is used, for example, if the structure from the outside has to be heated.

Thus, the thermoplastic material from the outside, ie from the fringes forth heated to softening temperature.

If only the surface layers or the interior of the thermoplastic be material heated, so the interior or the remain marginal layers in the solid state, worry this according to their deformation or mutual displacement by applying a restoring force for the shaping of the again solidifying material components and for the for later reshaping required in the state of matter Restoring force.

An alternative possibility for applying a deformation or to initiate the necessary force is the thermoplastic material with an element of a to provide shape memory alloy, which on heating the thermoplastic material on the softening temperature supporting structure deformed. The element or elements of a Shape memory alloy, with which the thermoplastic material is provided, may be formed in any manner be, for example as strips, plates, wires or rods. The elements may be present in the thermoplastic material be provided, or on the outside thereof.

For example, a sandwich structure can be provided, wherein the outer layers of a shape memory alloy exist, while the thermoplastic material, the intermediate layer forms.

Shape memory alloys by introducing thermal driven or electrical energy, which heats up this. After her transition from the martensitic phase in the austenitic phase called in. A_s-Temperature "Remind" them at its original un-deformed shape and can again so act as an actuator. In technically applicable Formedächtnislegierungen is the maximum A_s-Temperature between 120 ° C (Ni-Ti) and 170 ° C (Cu-Al-Ni).

In the aforementioned sandwich structure, for example, in optimized matching of material and geometry of the shape memory alloy layers and the thermoplastic core material control of deformation and structural rigidity recovery or locking of the structure alone by the convection heat of the thermoplastic material the inner layers are obtained.

For this purpose, for example, a thermoplastic with a melting temperature > 200 ° C. Prerequisite is already sufficient shear stiffness of the core falls below of A_s-Temperature To the withdrawal of the deformation effect the shape memory alloy to be prevented. That means, the material of the inner layer may only above the A_s-Temperature begin the shape memory alloy to soften and has on cooling before reaching the M_f-Temperature the shape memory alloy to be solidified. This through the choice of a shape memory alloy with correspondingly wider hysteresis can be achieved.

The M_fTemperature is the temperature at which a 100% Martensite is reached.

Thus, the invention is a supporting structure in Lightweight provided with integrated joint function, can be locked and released the joint, depending on if the thermoplastic material by turning on the heater heated to softening or when switched Heater has cooled. The invention supporting structure is used in particular in the automotive and aircraft industries.

The following are embodiments of the invention bearing Structure based on the drawing described in closer detail. Therein is shown highly schematically simplified<dl tsize="15"><dt>Fig. 1</dt><dd>a section through the flap of a aircraft;</dd><dt>FIGS. 2a and 2b</dt><dd>a section through the area A of the outer skin the flap of FIG. 1 in an enlarged view roughly waagrechtem or bent upward State.</dd></dl>

According to FIG. 1, the flap of an aircraft a front Section 1 and a trailing edge portion 2 which be streamlined adjoins the front portion. 1 The portion 2 has an outer skin 3, to the is attached to the front part. 1 According to FIG. 1, the trailing edge portion 2 between an upper, with continuous Lines drawn position and a lower, dot-dash Lines drawn position over the medium approximately horizontal, dashed line position with a not shown actuator adjustable.

According to Fig. 2a and 2b, to the outer skin 3 a sandwich structure , and although it consists of two outer Layers 5, 6, for example of metal or plastic and an inner layer 7 made of a thermoplastic material.

The thermoplastic material has a softening temperature of , which is substantially above the temperature of the Flaps is in flight operations. The outer layers 5, 6 are material-tight and have a burden for the Flaps sufficient bending and torsional. through their A distance from each other, they put a burden to occur sufficient flexural rigidity contrary. The thermoplastic Material of the inner layer 7 ensures solid Physical state sufficient rigidity of the section 2. It may to be provided with reinforcing fibers.

In the inner layer 7, the heating wires extend 8 an electrical Resistance heating. Thus, the thermoplastic Material 7 is heated in the shell 3 to softening , so that the outer skin 3 (and thus the portion 2) by applying a force according to arrow 9 in Fig. 2 with the actuator not shown in the position be bent as shown in FIG. 2b.

After switching off the heater 8 solidifies the thermoplastic Material of the inner layer 7 so that the outer skin 3 their new geometry maintains prerequisite is the maintenance the force according em arrow 9 until completion the transition from the softened in the solid phase of the thermoplastic material. After that ensures the full again existing rigidity of the inner layer 7 for fixing the deformed geometry and the provision of the structural Rigidity of the trailing edge 2. The speed of Increase rigidity of the thermoplastic material of the inner layer 7, by additional cooling during the accelerated phase of the solidification of the thermoplastic material will.