Abstract:
A heat shield includes a plurality of elements for shielding temperature-sensitive components. The elements are substantially matched to the respective contour of the component which is to be shielded and which at least partially overlap one another. The elements are fixed but moveable relative to one another in an overlapping region.

Description:
BACKGROUND ON THE INVENTION 
     1. Technical Field 
     The invention relates to a heat shield, composed of a plurality of elements, for shielding components influenced by temperature. 
     2. Related Art 
     The use of heat shields for shielding components influenced by temperature, such as vehicle exhaust manifolds or the like, is generally known. In the typically one-piece, rigidly connected heat shields used in this case, thermally-related changes in length of the particular component influenced by temperature may result in failure. Under the influence of temperature, exhaust manifolds in particular may expand by as much as 5 mm. This causes stress on the heat shield at the region of its attachment, which may lead to crack formation as the result of additional vibrations in the exhaust gas system. 
     In such cases decoupling elements are used as needed to address the referenced manifestations of failure. 
     A stationary heat shield is described in JP-A 2001347323 which has a sandwich structure and a plurality of uniform or nonuniform patterns having a hill-and-valley shape. This heat shield is securely connected via screws to the component to be shielded. The heat shield has a one-piece design, and is essentially adapted to the shape of the component to be shielded. The disadvantages previously described for the general prior art are present here as well. 
     Depending on the complexity of the component to be shielded, however, it is not always possible to provide a one-piece heat shield. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide a heat shield which may be adapted even to complex structures of a component to be shielded, and which can easily compensate for the thermally-related changes in length of the component, without the described technical problems. 
     This object is achieved by use of a heat shield, composed of a plurality of elements, for shielding components influenced by temperature, formed by elements which are essentially adapted to the respective contour of the component to be shielded and which at least partially overlap one another, wherein the elements are provided so as to be fixed at least in places but moveable relative to one another in the overlapping region. 
     By use of a heat shield composed of a plurality of elements, in which the individual elements are movable relative to one another, even more complicated structures of the component to be shielded may be easily adapted without resulting in the technical problems described at the outset. The individual elements are movable relative to one another in the region of their fixed attachment in order to allow for the thermally-related changes in length of the component to be shielded. 
     At least one fixing element is used which is provided in the region of adjacent elements. The fixing element allows the adjacent elements to be fixed in place in the region of at least one point, but to be movably supported relative to one another so that compensation may be made for thermally-related changes in length of the component, in particular a vehicle exhaust manifold, without damaging the heat shield. 
     The following advantages are also realized in comparison to the prior art:
         Prevention of stress cracks on the heat shield,   Reduction of attachment points for the individual elements,   A movable connection of two or more elements of a heat shield,   From a logistical standpoint, provision of a single heat shield formed from a plurality of elements, and   Capability for providing complex geometries of the components to be shielded.       

     Since the adjacent elements at least partially overlap one another, it may be sufficient for storage, transport, and installation purposes to join the adjacent elements together in an articulated manner solely in the region of a single point. Of course, if this is not sufficient, multiple fixing points may be provided. 
     According to a further concept of the invention, in an end region of one element a projection having an approximately platelike design is provided which faces in the direction of the adjacent element. The fixing point may then be provided in the region of the plate projection. 
     The fixing element itself advantageously has an approximately cross-shaped design, wherein the leg regions extending parallel to the elements form sliding surfaces for the individual elements to slide relative to one another in order to compensate for thermally-related changes in length of the component to be shielded. 
     Depending on the application, it may be meaningful to form profiles from the materials of the adjacent elements facing in the direction of the particular leg region, thereby forming point-shaped sliding elements. The leg of the fixing element which is not parallel to the elements may be designed as a hollow body, wherein the free leg ends, at least on the projection side, are bent, in particular flanged, in the direction of the projection. 
     The hollow body may also accommodate a rivet by means of which an articulated connection is then established between the adjacent elements. The particular type of connection established by one skilled in the art depends on the application. 
    
    
     
       THE DRAWINGS 
       The subject matter of the invention is illustrated in the drawing with reference to one exemplary embodiment, and is described below. The drawings show the following: 
         FIG. 1  shows a three-dimensional illustration of a component to be shielded by a multipart heat shield; and 
         FIG. 2  shows a partial illustration of the fixing region for two elements of a heat shield. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a three-dimensional illustration of a heat shield  1 , which in this example comprises two elements  2 ,  3 . In addition, in the present example the heat shield  1  is intended to shield an exhaust manifold  4 , which is only indicated. The exhaust manifold is part of an exhaust gas system, which in region  5  may contain an exhaust gas turbocharger, for example. Shown are the connection regions  6  on the engine side for the exhaust manifold  4 , which comprises a geometrically complex structure in the direction of region  5 . Accordingly, the individual elements  2 ,  3  likewise have different contour designs, i.e., are approximately adapted to the geometric structure of the exhaust manifold  4 . Element  2  has an attachment region  7  on the exhaust manifold  4 , and element  3  has an attachment region  8  on the exhaust gas turbocharger  5 , by means of which said elements may be mounted securely to the referenced components. Different temperatures occur in the components  4 ,  5  used in the present example. The region of the exhaust gas turbocharger  5  has a higher temperature level than the exhaust manifold  4 , resulting in different thermal expansions in the region of the heat shield  1  which have different effects on the individual elements  2 ,  3 . 
     On element  3  a projection  9  having a platelike design is provided which faces in the direction of element  2  and which in the region of its free end has an oblong hole  10  which is used for accommodating a fixing element  11 . By means of the fixing element  11 , which is only indicated here, elements  2 ,  3  are fixed relative to one another, but in a manner which allows motion of the two elements relative to one another. This is not shown in  FIG. 1 . 
       FIG. 2  shows the fixing region  12 . The fixing element  11  illustrated in  FIG. 1  is used, and in the present example has a cross-shaped design with two leg regions  13 ,  14  extending parallel to elements  2 ,  3 . The leg  15  of the fixing element  11  extending perpendicular to the leg regions  13 ,  14  has a hollow design. Of element  3 , only the platelike projection  9  is shown. The same applies for the oblong hole  10 . In the region of overlap with element  3 , element  2  is likewise provided with a hole  16  oppositely situated from the oblong hole  10 . The fixing element  12  thus projects with its leg through the oblong hole  10  and also through the hole  16 , whereas the leg regions  13 ,  14  form sliding regions which allow appropriate compensation to occur when elements  2 ,  3  move relative to one another, without resulting in stress cracks in the region of the elements  2 ,  3 . If necessary, profiles  17  which face the particular leg region  13 ,  14  may be integrally molded onto the respective element  2 ,  3 , on the platelike projection  9  and also on the overlap region of element  2 , by means of which a sliding motion of the respective element  2 ,  3  relative to the associated leg region  13 ,  14  may be provided in places. To prevent the fixing element  11  from coming loose between elements  2 ,  3 , on the one hand at least one of the free ends  18  of the leg  15  may be flanged, for example in the direction of the platelike projection  9 . If necessary, this may also be performed in the region of both free ends  18 . On the other hand, a separate rivet  19  may be provided in the region of at least one of the two ends  18 . 
     Alternatively, it is also possible to guide a rivet (not illustrated) through the cavity  20 , and to press the rivet flat in the end regions, forming a rivet head.