Apparatus and method for drawing metal tube

Abstract

In an apparatus for drawing a metal tube in which lubrication oil is ejected from an ejecting opening formed in a hollow rod supporting a plug to apply the lubrication oil onto an inner surface of a raw tube, the lubrication oil ejection responsiveness when a discontinuous lubrication oil supply is performed is enhanced. In the drawing apparatus in which a metal raw tube ( 2 ) is processed by passing the same between a die ( 10 ) for forming an outer surface and a plug ( 11 ) for forming an inner surface, an ejecting opening ( 21 ) from which lubrication oil (L) is ejected opens into an outer peripheral surface of a hollow rod ( 20 ) supporting the plug ( 11 ). The ejecting opening ( 21 ) is provided only in a region of the rod ( 20 ) higher than the center thereof in the up-and-down direction.

1 - 10 . (canceled) 
     
     
         11 . A drawing apparatus for a metal tube for processing a metal raw tube by passing a metal raw tube between a die for forming an outer surface and a plug for forming an inner surface, characterized in that an ejecting opening for ejecting lubrication oil opens into an outer peripheral surface of a hollow rod supporting the plug, wherein the ejecting opening is provided only at a region above a center of the rod in an up-and-down direction. 
     
     
         12 . The drawing apparatus for a metal tube as recited in  claim 11 , wherein a distance between the ejecting opening and a bearing portion of the plug in a drawing direction is 20 cm or less. 
     
     
         13 . The drawing apparatus for a metal tube as recited in  claim 11 , wherein a nozzle protruded from the outer peripheral surface of the rod is provided at the ejecting opening. 
     
     
         14 . The drawing apparatus for a metal tube as recited in  claim 12 , wherein a nozzle protruded from the outer peripheral surface of the rod is provided at the ejecting opening. 
     
     
         15 . The drawing apparatus for a metal tube as recited in  claim 11 , wherein the ejecting opening opens toward a front side of the apparatus. 
     
     
         16 . The drawing apparatus for a metal tube as recited in  claim 12 , wherein the ejecting opening opens toward a front side of the apparatus. 
     
     
         17 . The drawing apparatus for a metal tube as recited in  claim 13 , wherein the ejecting opening opens toward a front side of the apparatus. 
     
     
         18 . The drawing apparatus for a metal tube as recited in  claim 14 , wherein the ejecting opening opens toward a front side of the apparatus. 
     
     
         19 . The drawing apparatus for a metal tube as recited in  claim 11 , wherein the ejecting opening is provided within an angle range of 60° or less from an apex of the rod with respect the center of the rod. 
     
     
         20 . A drawing method for a metal tube for sequentially drawing a plurality of metal raw tubes using the drawing apparatus as recited in  claim 11 . 
     
     
         21 . A drawing method for a metal tube for sequentially drawing a plurality of metal raw tubes by repeating the following steps (i) to (v) using the drawing apparatus as recited in  claim 11 :
 (i) a step of drawing a raw tube while supplying lubrication oil onto an inner surface of the raw tube by ejecting the lubrication oil supplied to an inside of a hollow rod supporting a plug;   (ii) a step of suspending supply of the lubrication oil after completion of drawing the raw tube;   (iii) a step of taking out the drawn tube from the drawing apparatus and setting a subsequent raw tube to the drawing apparatus;   (iv) a step of resuming supply of the lubrication oil; and   (v) a step of returning to the step (i).