Apparatus and method for hydroforming a tubular part

Abstract

A method and apparatus for shaping a raw tube into a formed part. The part can be configured within a die assembly including a hydroforming die structure and a pair of tube-engaging punches. The punches are inserted into the ends of the raw tube to shape the ends into the desired configuration. The middle portion of the raw tube is shaped into the desired configuration by hydroforming. Thus, the method and apparatus can shape the raw tube along its entire length, leaving no remnants of the raw tube that must be trimmed away.

1 . A hydroforming die assembly  10  for hydroforming a part from a tubular blank  40 , said part having a desired configuration different from a configuration of said blank and including a desired cross section at one end thereof, said die assembly  10  including a die structure having interior surfaces defining a die cavity  52 , said die cavity  52  having a cross sectional configuration conforming generally to the desired exterior shape of said part, said die assembly  10  further comprising: 
 a pair of tube-end engaging structures  81  disposed at opposite ends of said die cavity  52  and constructed and arranged to engage opposite ends of said tubular blank  40 , said tube-end engaging structures  81  being constructed and arranged to seal said opposite ends of said tubular blank  40  and to pressurize hydroforming fluid within said tubular blank  40  for expanding said tubular blank  40  into conformity with said interior surfaces of said die cavity  52 , a first of said tube-end engaging structures  81  having an outer cross-sectional configuration corresponding to said desired cross section at said one end of said part, said first of said tube-end engaging structures  81  being movable into forced engagement with one end of said tubular blank  40  to conform said one end of said tubular blank  40  to said outer cross-sectional configuration of said first of said tube-engaging structures  81  and hence said predetermined cross section at said one end of said part.    
     
     
         2 . A hydroforming die assembly  10  according to  claim 1 , wherein 
 said first tube-end engaging structure  81  has an exterior surface including a beveled portion  82  which is partially inserted into said one end of said tubular blank  40 , said first tube-end engaging structure  81  being moved further into said one end of said tubular blank  40  so as to cause inner surface portions of said one end of said tubular blank  40  to slide in forced relation along said beveled portion  82  and cause said one end of said tubular blank  40  to be deformed i) over said first tube-end engaging structure  81  and ii) into conformity with said exterior surface of said first tube-end engaging structure  81 , and wherein one end of said die cavity  52  receives said first tube-engaging structure  81 , said interior surfaces of said die cavity  52  at said one end of said die cavity  52  having a configuration conforming to an exterior surface configuration of said part at said one end of said part.    
     
     
         3 . A method of producing a hydroformed part using a hydroforming die assembly  10  for hydroforming a part from a tubular blank  40 , the part having a desired configuration different from a configuration of the blank and including a desired cross section at one end of the part, the die assembly  10  including a die structure having interior surfaces defining a die cavity  52 , the die cavity  52  having a cross sectional configuration conforming to the desired cross section of the part, the method comprising the steps of: 
 providing and a pair of tube-end engaging structures  81  disposed at opposite ends of the die cavity  52  and constructed and arranged to engage opposite ends of the tubular blank  40 , the tube-end engaging structures  81  being constructed and arranged to seal the opposite ends of the tubular blank  40  and to pressurize hydroforming fluid within the tubular blank  40  for expanding the tubular blank  40  into conformity with the interior surfaces of the die cavity  52 , a first of the tube-end engaging structures  81  having an outer cross-sectional configuration corresponding to the desired cross section at one end of the part;    moving the first of the tube-engaging structures  81  into forced engagement with one end of the tubular blank  40  to conform the one end of said tubular blank  40  to the outer cross-sectional configuration of the first of the tube-engaging structures  81  and hence the predetermined cross section at the one end of the part; and    applying pressure within the tubular blank  40  to form the tubular blank  40  in to the desired configuration of the part.    
     
     
         4 . A method according to  claim 3 , further comprising the step of: 
 incorporating the part into a product without cutting off the one end of the part formed by the forced engagement of the first of the tube-engaging structures  81 .    
     
     
         5 . A assembly according to  claim 1 , wherein 
 a first of said tube-engaging structures  81  has a forward end  33  and a lateral shoulder  88  protruding from a multifaceted portion  84  such that the first of said tube engaging structures  81  can be inserted into said tubular blank  40  continuously from the forward end  33  of said tube-engaging structure to said lateral shoulder  88  along said multifaceted portion  84  until said lateral shoulder  88  abuts said tube-engaging structure  81  and halts further insertion of said first of said tube-engaging structures  81  relative to said tubular blank  40 .    
     
     
         6 . A method according to  claim 3 , wherein 
 the moving of the first of the tube-engaging structures  81  includes inserting the first of the tube-engaging structures  81  into the tubular blank  40  continuously from a forward end  33  of the first of the tube-engaging structures  81 , along a multifaceted portion  84  of the first of the tube-engaging structures  81 , and to a lateral shoulder  88  of the first of the tube-engaging structures  81  that protrudes from the multifaceted portion  84 , until the lateral shoulder  88  abuts the end of tubular blank  40  and halts further insertion of the tube-engaging structure  81  relative to the tubular blank  40 .    
     
     
         7 . A method according to  claim 3 , wherein 
 the moving of the first of the tube-engaging structures  81  into forced engagement with one end of the tubular blank  40  is a complete insertion of the first of the tube-engaging structures  81  into the tubular blank  40  and a complete reconfiguration of the one end of the tubular blank  40  into the final, desired configuration of the part by fully forcing the one end of the tubular blank  40  to conform to the outer surface of the first of the tube-engaging structures  81  and to the inner surface of the die cavity  52 .