Mercedes-benz Aktiengesellschaft

Thoralf Nehls

Pierre Bonny

Thomas Huelsberg

Eckhard Reese

Henning Bloecker

Ralf Puenjer

Heinz-Ruediger Otte

The invention relates to a method and a device for manufacturing T-pieces from an unbranched starting piece of pipe by means of internal high-pressure forming (IHF). For this purpose, the starting piece of pipe is placed in a two-part forming tool which gives the shape, can be opened and closed, surrounds the starting piece of pipe, and has a cutout corresponding to the desired shape of the T-shaped pipe branch. Placed in a sealing manner against the two open end faces of the inserted starting piece of pipe in each case is a plunger which is movable in the forming tool and can be pushed axially into the forming took in each case by a pressure cylinder. The interior of the starting piece of pipe is filled with pressure fluid by means of an opening in at least one of the plungers, prior to being placed on the plungers in a sealing manner. A fluid high-pressure is built up by pushing the plungers axially into the forming tool with high force and, thus initiated, by pushing pipe wall material axially towards the forming point, the pipe wall material is pressed into the cutout in the forming tool and the T-shaped branch is thus shaped. In order to be able to manufacture T-pieces with a curved branch, the end face of the T-shaped cutout for the pipe branch is supported with controllable force by means of a flexible mandrel.

Method of manufacturing a branched pipe by internal high-pressure forming

A device for producing a hollow body according to an internal high pressure metal forming process has a tool which is divided along a mold joint into a stationary tool part and a liftable tool part. The tool has an impression for receiving a tube-shaped blank. A press opens and closes the tool. An axially movable slide is attached to an open end of the blank, through which a pressure medium is introduced into the blank. A hydraulic working cylinder which is angularly and vertically adjustable on a support member has a piston rod which holds the slide and which displaces the slide axially. A pair of pull rods connect the tool and the working cylinder and are arranged on opposite sides of the piston rod at the same level as the piston rod, each pull rod extending into the end-side portion of the mold joint and being releasably anchored to each of the stationary tool part and the liftable tool part in a form-locking manner in corresponding recesses along the mold joint. The recesses are configured such that after a working cycle the liftable tool part can be lifted away from the pull rod in a vertical direction without resistance. In another embodiment the pull rods are releasably anchored to a holding wall in a form-locking manner in corresponding recesses, the holding wall being stationarily fastened to the stationary tool part.

Device for producing hollow bodies according to an internal high

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Hamburg, Germany

Thoralf Nehls