Hydroforming Unit

Abstract

A hydroforming unit comprises a mould ( 19,20 ) that can be opened and sealing arrangements ( 30 - 33; 35 - 39 ) for sealing the ends of a tube-formed blank ( 16 ) placed in the mould, each one of the sealing arrangements ( 30 - 33; 35 - 39 ) comprises a ring ( 30, 35 ) with a thin wall that fits into the inner surface of the tube ( 16 ), and a plug ( 33, 36 ) that can be displaced in an axial direction mounted axially inside of the ring, and an arrangement ( 32,37 ) for initially drawing the plug ( 33, 36 ) outwards to put the ring under elastic tension against the inside of the tube-formed blank so that the plug and the ring together form a seal.

1 . A hydroforming unit comprising a mould ( 19 , 20 ) that can be opened and sealing arrangements ( 30 - 33 ;  35 - 39 ) for sealing the ends of a tube-formed blank ( 16 ) placed in the mould,
 characterised in that   each one of the sealing arrangements ( 30 - 33 ;  35 - 39 ) comprises a ring ( 30 ,  35 ) with a thin wall that fits into the inner surface of the tube ( 16 ), and a plug ( 33 ,  36 ) that can be displaced in an axial direction mounted axially inside of the ring, at least one of the ring and the plug having a conical form such that the plug and the ring together form a seal that is self-locking inside of the tube ( 16 ).   
     
     
         2 . A hydroforming unit according to  claim 1 , characterised by an arrangement ( 32 , 37 ) for initially drawing the plug ( 33 ,  36 ) outwards to put the ring under elastic tension against the inside of the tube-formed blank.