Tube and machining device and method for manufacturing the same

Abstract

A machining device used to machine a workpiece into a tube includes a punch and a cavity die. The cavity die includes a cavity and an extruding portion. The extruding portion is curved. The unilateral clearance between the punch and the cavity die is less than a thickness of the sidewall. A method for manufacturing a tube is also provided.

1 . A machining device machining a workpiece comprising a sidewall, the machining device comprising:
 a punch; and   a cavity die, comprising:
 a cavity; and 
 an extruding portion; wherein the extruding portion is curved and a unilateral clearance between the punch and the cavity die is less than a thickness of the sidewall of the workpiece. 
   
     
     
         2 . The machining device of  claim 1 , wherein the unilateral clearance between the punch and the cavity die is less than a thickness of the sidewall by about 0.35 mm to about 0.5 mm. 
     
     
         3 . The machining device of  claim 1  further comprising at least one unloading subassembly positioned at an end of the cavity die away from the extruding portion, wherein the at least one unloading subassembly comprises an unloading member and an elastic member resisting each other, and the unloading member resists the punch by an elastic force of the elastic member. 
     
     
         4 . The machining device of  claim 3 , wherein the at least one unloading subassembly comprise two unloading subassemblies, each unloading subassembly positioned on one end of the cavity die away from the extruding portion, and at opposite sides of the cavity. 
     
     
         5 . The machining device of  claim 4 , wherein the unloading member forms a resisting portion comprising a guiding surface facing the cavity to facilitate the workpiece sliding through the unloading subassembly. 
     
     
         6 . The machining device of  claim 5 , wherein the guiding surface of the resisting portion facing the cavity is curved. 
     
     
         7 . The machining device of  claim 6 , wherein the resisting portion further comprises a planar surface opposite to the guiding surface. 
     
     
         8 . A method of manufacturing a tube, the method comprising:
 providing a workpiece comprising a sidewall;   providing a machining device comprising a punch and a cavity die, the cavity die comprising a cavity and a curved extruding portion, a unilateral clearance between the punch and the cavity die being less than a thickness of the sidewall of the workpiece, and the workpiece sleeved on the punch; and   impelling the workpiece towards the cavity die via the punch, wherein the sidewall is extruded to a thickness equal to the unilateral clearance by the extruding portion, and the reducing material on the transverse direction of the sidewall moves along a longitudinal axis of the punch to increase the size along the longitudinal axis of the workpiece.   
     
     
         9 . The method for manufacturing a tube of  claim 8 , wherein the workpiece is formed by forging and backward extrusion. 
     
     
         10 . The method for manufacturing a tube of  claim 8 , wherein the unilateral clearance between the punch and the cavity die is less than a thickness of the sidewall by about 0.35 mm to about 0.5 mm. 
     
     
         11 . The method for manufacturing a tube of  claim 8 , further comprising an unloading subassembly positioned at an end of the cavity die away from the extruding portion, wherein the unloading subassembly comprises an unloading member and an elastic member resisting each other, and the unloading member resists the punch by an elastic force of the elastic member. 
     
     
         12 . The method for manufacturing a tube of  claim 11 , further comprising another unloading subassembly, both unloading subassemblies positioned on one end of the cavity die away from the extruding portion and at opposite sides of the cavity. 
     
     
         13 . The method for manufacturing a tube of  claim 12 , wherein the unloading member forms a resisting portion comprising a guiding surface facing the cavity to facilitate the workpiece sliding through the unloading subassembly. 
     
     
         14 . The method for manufacturing a tube of  claim 13 , wherein the guiding surface of the resisting portion facing the cavity is curved. 
     
     
         15 . The method for manufacturing a tube of  claim 14 , wherein the resisting portion further comprising a planar surface opposite to the guiding surface. 
     
     
         16 . A tube, comprising:
 a sidewall; and   a bottom wall;   wherein the tube is formed by extruding a single workpiece, the height to width ratio of the tube exceeds 9:1 or the height to width ratio of the tube exceeds 6:1 when an angle formed by the bottom wall and the sidewall of the tube is a taper angle.