Daimler Chrysler Ag

Mercedes-benz Aktiengesellschaft

Thomas Hulsberg

Pierre Bonny

Henning Blocker

Ralf Punjer

Uwe Hardtke

Thorsten Sternal

Ulrich Haag

The invention relates to a process and apparatus for the forming of a hollow body. The process includes providing a forming mold comprising an upper mold and a lower mold which form a mold cavity having a cross-sectional contour in a closed state of the forming mold. The upper mold includes a roller. The hollow body is placed between the upper mold and the lower mold in an area of the mold cavity. The hollow body is preprofiled by moving at least one of the upper mold and the lower mold into the closed state at which time the roller comes into frictional contact with a surface of the hollow body running at an acute angle with respect to a direction of the movement of the at least one upper mold and lower mold. The preprofiled hollow body is then formed into a final shape corresponding to the cross-sectional contour of the forming mold by applying a hydraulic internal pressure into the preprofiled hollow body and expanding the hollow body while the upper mild and the lower mold are in the closed state. By way of the present invention, a hollow body can be reliably formed while significantly reducing the stress on the hollow body.

Method and device for forming a hollow body

A built-up airgap-insulated exhaust manifold of an exhaust system of a motor vehicle includes at least two exhaust pipes with an inlet flange attached in each case to one end and to be fastened to the cylinder head of an internal combustion engine of a motor vehicle. The exhaust pipes include a pipe bend and at least one branched pipe piece connected to the latter. If a plurality of branched pipe pieces are arranged they are connected to one another in a row and the last pipe piece in the row forms a header connected at one end to the exhaust tract leading further on in the exhaust system. The exhaust manifold has at least one exhaust pipe, which is designed as a double pipe with airgap insulation between an outer and an inner pipe, and possessing at least one exhaust pipe without an air insulation gap. The outer pipe and the inner pipe of the airgap-insulated exhaust pipe bear against one another at the end which is plugged together with and welded to an associated inlet flange.

Built-up airgap-insulated exhaust manifold of a motor vehicle and method for producing it

A method and a device for producing holes in the circumference of a hollow shape, with a wall piece being separated as a slug from the hollow shape in an internal high-pressure mold and being jammed without projecting relative to the outer circumference of the hollow shape in a previously produced hole. In order to remove the slug produced during punching in simple fashion from the internal high-pressure mold, the separated slug is jammed at a fluid pressure that is reduced relative to an internal high fluid pressure without loss via a punch and can separate the slug following removal of the finished hollow shape from the internal high-pressure mold, from the hollow shape, finally clearing the hole.

Method and device for making holes at the circumference of a hollow shape

A fan-type manifold for multi-cylinder internal-combustion engines has several first individual pipe sections which are connected in pairs to respective ones of second pipe sections. The first individual pipe sections are undeformed on the end and are cut off at a specific angle. The second pipe sections are produced by an internal high pressure deforming process. The first pipe sections are plugged into the second pipe sections at respective Y-type combining points to form Y-shaped connections and are sealingly welded to each other via surrounding fillet welds. One of the second pipe sections has an additional Y-type combining point for the lateral connection of the other second pipe sections, which are sealingly welded thereto via surrounding fillet welds.

Fan-type exhaust gas manifold for multi-cylinder internal-combustion

An exhaust manifold for an internal combustion engine with at least two cylinders includes at least two adjacent connection branches which are interconnected by collection pipe sections having an expansion compensating bellows for accommodating differential thermal expansion therebetween and a gas flow guide pipe structure which extends into the bellows. At least one of the collection pipe sections comprises a multi-layered pipe wall with which the expansion compensating bellows is integrally formed.

Growing community of inventors

Rosengarten, Germany

Thomas Hulsberg