Patent Application
20060219433
The invention relates to a shielding component, in particular a heat shield, consisting of shield components which are made flat, which lie at least partially on top of one another, and which are connected to one another at least partially along at least one common connecting line, along the common connecting line at least one shield component encompassing another shield component in an overlap.
While heat development, for example of a high-economy, performance-optimized diesel engine, can be very low on the cylinder crankshaft housing, this in no way applies to “hot zones” such as manifolds, turbocharger, catalytic converter, etc. Due to the more and more compact construction of engines, components which are not thermally “compatible” are increasingly ending up in close proximity to one another. Accordingly, it is necessary to protect thermal engine components against adjacent, heat-sensitive assemblies, such as sensors, fuel lines, pressure cells, body parts, etc. The situation is also exacerbated by the compact structure in that the high packing density of the assemblies constricts the cooling air flow in the engine compartment. Noise abatement measures can also contribute to this. Thus, for example, plastic bottom plates which are designed to reduce the emission of noise from the engine compartment to the roadway, under certain circumstances can produce effective insulation with which heat is enclosed in the engine compartment. Catalytic converters, due to their phased high surface temperature, are considered to be among the heat sources which certainly may necessitate the use of protective shield barriers. One typical example of this is design measures such as positioning the catalytic converter close by the manifold. This design principle which performs the function of rapid heat-up of the catalytic converter and thus for reducing emissions in the cold start phase shifts a major source of heat into the engine compartment where numerous assemblies are crowded in a tight space. Certainly, one reason for the growing importance of shielding components such as heat shields is the trend toward use of thermoplastics. The light and economical materials with their exceptional moldability are rapidly becoming common in the engine compartment, but require special attention with respect to ambient temperatures at the application site relative to other thermal engine parts (“New materials and development tools for heat protection”, in MTZ 12/2001, Vol. 72, pp. 1044 ff).
DE 102 47 641 B3 discloses a structural component, especially in the form of a noise-damping shielding component, as a component of a motor vehicle. To improve acoustic insulation in the known shielding component, it consists of shield components which are made flat, which lie at least partially on top of one another, which accommodate an insulating intermediate layer between themselves, and which are joined to one another on the outer circumferential side along a common connecting line for secure connection to one another, by one shielding component with overlap of the insulating intermediate layer encompassing the other shielding component in the same overlap in the manner of flanging. This known positive-locking connection fixes the individual layers or shield components immovably relative to one another and as a result of the connection which is produced to be rigid in this way, especially in thermal expansion processes for the shielding component, problems arise in fixing it, especially when, as in the indicated known solution, the shielding component is fixed within the engine compartment on the stationary parts there by way of angular bracket legs which act on the edge side. In addition to possible warping of the multilayer shielding component with potential bulging and tearing of the heat shield material, which can lead to failure of the shielding component, nor can it be precluded that the angular bracket legs as fixing means become detached from the engine components by way of the provided screw connection and in this way release the shielding component; this can entail the corresponding repair and maintenance. The known solution is also expensive to implement, since angular bracket legs must be provided in addition for fixing. This also increases the installation cost in production lines of motor vehicles.
On the basis of this prior art, the object of the invention is to further improve the known solutions while maintaining their advantages, specifically to ensure very good acoustic and heat insulation, such that even under strong thermal stress reliable operation is ensured, and that less installation space is required with simultaneously increased stiffness and strength. This object is achieved by a shielding component with the features specified in claim 1 in its entirety.
In that, as specified in the characterizing part of claim 1, within the overlap at least in part the shield components are held by frictional engagement so as to be displaceable against one another relative to a compensation distance, a rigid connection of the shield components with their individual layers is avoided and rather, depending on the thermal situation, they can mutually “slide” off one another without in this way the connection being adversely affected along the common connecting line. Based on the allowed relative displacement motion of the shield components to one another, bulging effects on the shield components are avoided and they do not tear, not even in the area of their attachment to other machine or vehicle parts. Since in any thermal situation and in any fixing state the frictional connection of the shield components with the displacement possibility is maintained, the shielding component as claimed in the invention can also be used in such thermally stressed zones, for example directly in the gasket area of the cylinder head gasket, where previous use of these shield components was not possible.
The indicated frictional connection which is achieved by the positive-locking overlap along the connecting line by means of the respective shield components moreover ensures that additional fasteners can be omitted and the indicated shielding component can be fixed directly by way of fixing means, such as screws or the like, on other machine and engine parts. Since, as described, additional fasteners such as the angular bracket legs can be omitted, additional parts are not necessary in the installation of the shielding component; this accordingly helps to reduce production and installation costs. A stiff and high-strength shielding component structure is also achieved by the use of several shield components.
With the shielding component as claimed in the invention, it is possible for the first time to provide a conventional, multi-layer heat shield with a gasket which helps seal fluid passage through the shielding component in hot areas, for the purpose of a static gasket the sealing function being maintained to the full extent, even if the shield components and their layers should move relative to one another due to heat.
Other advantageous embodiments of the shielding component as claimed in the invention are the subject matter of the other dependent claims.
The shielding component as claimed in the invention will be described in greater detail below using one embodiment as shown in the drawings in which in diagram form and not drawn to scale
The shielding component as claimed in the invention is made in particular as a heat shield and consists at least in the middle area of individual shield components 10, 12, 14 which lie partially flat on top of one another. These shield components 10, 12, 14 are connected to one another along a common connecting line 16, along this common connecting line 16 the bottom shield component 14 which is shown in
As furthermore is to be seen in the figures, the indicated connecting line 16 runs in an arc and encompasses especially a round passage opening 22 which passes through all shield components 10, 12, 14 and which is used for possible passage of the fluid flow, which can also be gaseous.
The middle shield component 12 which is bordered in the middle area by the two shield components 10, 14 is preferably made as a formed sheet metal part and has covering surfaces 24 which are bent at least partially on the edge side and which contribute to ensuring thermal and/or acoustic insulation. The pertinent middle shield component 12 consists of several layers, especially three layers, two sheet metal cover layers being able to accommodate between themselves an insulating intermediate layer which is not detailed and in this way overlap it. The structure of such heat shields is conventional and is described for example in DE 10 2004 030 621 which was published subsequently, so that it will not be detailed here. So that the two sheet metal cover layers of the middle shield component 12 hold fast to one another, provision is made on the exterior circumferential side such that the top sheet metal cover layer at least partially covers the lower sheet metal cover layer by means of flanging 28 which for the sake of easier representation is only partially reproduced in
As the figures furthermore show, the overlap 18 takes place along the connecting line 16 which forms the passage opening 22, in addition to the overlap 18 which is shown especially in
Based on the cited frictional connection of the individual shield components 10, 12, 14 to one another, even under thermal stress the relative position of the shield components to one another is maintained, such that the gasket 30 can perform its function in operation even under high thermal stress. Since the respective projection 32 which forms the gasket 30 is an integral component of the shield component 10 and of the shield component 14, in the installed state of the shielding component the middle shield component 12 remains in its installation position and relative to this stationary installation position the two shield components 10, 14 which are connected to one another are displaced conforming to direction in the same respective directions. Since the overlap 18 in the area of the edge mounting 20 as shown in
The individual shield components 10, 12, 14 congruently have further passage openings 34, also in the form of an elongated hole, the other pertinent passage openings 34 being used to fix the shielding component on engine or machine components by means of conventional fixing means, such as screws.
With the solution as claimed in the invention it is ensured in any case that individual attachment points do not unintentionally detach from the shielding component or that cracks cannot form on the shielding component as a result of thermal stresses. Based on the possible displacement motion of the individual layers, the sealing function is safeguarded by way of the gasket 30 in any working situation and in this way reliable sealing of the passage opening 22 is achieved, so that the fluid flow which is to be controlled retains its fluid guidance and cannot emerge into the environment.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2005 015 244.9 | Apr 2005 | DE | national |
