Internal-combustion engines – Intake manifold
Reexamination Certificate
2002-05-31
2003-06-17
McMahon, Marguerite (Department: 3747)
Internal-combustion engines
Intake manifold
C123S184240, C123S184420, C123S184470, C123S184610
Reexamination Certificate
active
06578537
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to an intake device for an internal combustion engine which comprises at least two shells welded together at mating joint surfaces.
Intake devices of this type are known from European Patent Application No. EP 568,560, for example. According to this document, an intake device is constructed as a hollow chambered structure made of synthetic resin material, comprising a plurality of shells welded together which form the hollow chambers provided within the structure. These hollow chambers comprise primarily the collection chamber and the intake ducts which branch off therefrom. The intake ducts in intake devices often have a curved design due to the installation conditions and the required flow geometry. In these cases, the partition line which encompasses the mating joint surfaces for the weld also has a curved design.
To weld the shells of the intake device, a joining force is applied which ideally is perpendicular to the alignment of the partition line. A compromise must therefore be made when curved partition lines are present, since the effective joining force provided is diminished for the welding of partition lines which are obliquely inclined to the welding direction. According to EP 568,560, it is possible to achieve an inclination to a plane perpendicular to the direction of the welding force (“welding direction” for short) up to not substantially exceeding 60°.
Accordingly, the welding direction is most advantageously specified when the curved partition line has a similar angle on both ends with respect to the direction of the welding force. The transverse forces which arise during welding as a result of the inclination of the partition line are thereby compensated for or offset. Frequently, however, as a result of the geometry, it is not possible to orient the pressure force for the welding in the optimum way described above. Specifically, the shells of the intake pipe often have an outer contour which does not allow the welding tool to be applied in the ideal welding direction, thus requiring a deviation therefrom. In this case, disadvantageous transverse forces arise during the welding process which must be compensated for by appropriately dimensioning the welding tools or the welding machine. Designing the equipment to accommodate the high transverse forces thus results in additional costs which adversely affect the economy of the welded intake pipe. In addition, the transverse forces can cause the shells to shift during the welding process, resulting in lowered quality of the welding seam and tolerance problems with the finished parts.
SUMMARY OF THE INVENTION
The objects of the invention, therefore, are to provide an intake device for an internal combustion engine which can be welded independent of the external geometry, thereby obtaining an optimal result with regard to the economy and quality of the welding seam.
These and other objects are achieved in accordance with the present invention by providing an intake device for an internal combustion engine, comprising an inlet, cylinder-side outlets for combustion air, and duct structures which form communicating connections between the inlet and the outlets, wherein the duct structures are formed at least partially by at least two shells welded together along a partition line under application of a welding pressure force; the partition line being defined by mating joint surfaces on the shells which at least in partial regions are oriented at an angle of less than 90° relative to the welding pressure force; wherein the application of the welding pressure force on the sum of the partial regions generates a first transverse force Q
1
relative to the welding pressure force during welding of the intake device, and wherein additional mating surfaces are arranged within the shells which during application of the welding pressure force create a second transverse force Q
2
relative to the welding pressure force, the second transverse force Q
2
at least partially offsetting the first transverse force.
The invention is based on the principle that at least partial compensation must be made for the transverse forces resulting from the geometry of the partition line and the choice of the welding direction. If this compensation is achieved by forming contacting surfaces which are involved in the welding, the transverse forces can be offset or equalized in the component itself. Thus, the transverse forces are not transmitted to the molds, but instead are intercepted by the component itself. As a result, the welding tools may be designed with smaller dimensions, so that the components may be produced more economically.
In addition, the compensation of transverse forces resulting from the component geometry produces better welding results with respect to quality of the welding seams, since equalization of the transverse forces prevents the two shells to be welded from shifting in the direction of the transverse forces. The described measures also allow the intake devices to satisfy more stringent dimensional tolerance requirements. This further simplifies the installation of the intake pipe on the internal combustion engine, thereby increasing the economy of the proposed solution.
The intake device according to the invention comprises at least two duct structures which connect an inlet for combustion air to cylinder-side outlets in a known manner. The cylinder-side outlets are usually integrated into a cylinder head flange which facilitates installation of the intake device on the internal combustion engine. The inlet generally opens into a collection chamber from which at least one intake duct per cylinder leads to the cylinder-side outlets. The collection chamber therefore serves to distribute the combustion air to the individual cylinders. The described minimum requirements for the geometry of the duct structures can be supplemented by additional functions. For example, longer and shorter intake ducts may be provided which are switched by corresponding valves, depending on the operating mode of the internal combustion engine.
In order to satisfy the complex geometric requirements for the duct structures, the duct structures are formed at least partially from at least two shells which have a partition line along which the shells may be welded together upon application of a pressure force. For this purpose the vibration welding method is particularly useful, in which a high-frequency relative motion between the shells is produced which causes the shells to fuse at joint surfaces which mate with each other along the partition line, thereby joining the shells. Any desired number of individual shells may be combined with one another if adaptations are made for the complexities of the geometry of the intake device.
To form the geometry of the duct structures, the partition line between the shells is configured, in at least partial regions, at an angle of less than 90° with respect to the pressure force required for welding. As already mentioned, this results in creation of transverse forces during the welding. The partition line has corresponding joint surfaces in the intake pipe according to the invention. Joint surfaces in the sense of the invention refer to those surfaces that are necessary to join the two shells to one another so that the intake device forms a sealed, hollow chambered structure which can withstand the required bursting pressure. The sum of the partial regions having an angle less than 90° with respect to the pressure force results in a first transverse force which is not zero and which is transmitted to the welding tools.
The intake device according to the invention is characterized by the fact that within the shells are arranged corresponding additional surfaces which at least partially compensate for the first transverse force by creating a second transverse force which opposes the first transverse force. Preferably, of course, the first transverse force is completely offset; however, the described advantages of the invention are also obtained to a lesser ext
Klotz Arthur
Koch Ingo
Pietrowski Herbert
Teschner Matthias
Crowell & Moring LLP
Filterwerk Mann & Hummel GmbH
McMahon Marguerite
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