Molding method and molding apparatus

Abstract

The present invention relates to a molding method of reducing a diameter in an end portion of a metal tube to be characterized in having a step of rotating a metal tube around an axial core or rotating a frame in which a plurality of ring-shaped tools are arranged, and moving the axial core of the ring-shaped tool away from the axial core of the metal tube while moving the metal tube or the frame, thereby reducing the diameter in an end portion of the metal tube.

1 . A molding method of reducing a diameter in an end portion of a metal tube comprising the following steps: 
 a step of arranging a plurality of ring-shaped tools arranged with an axial core which is in parallel to an axial core of the metal tube having the end portion to be reduced in the diameter and having an inner periphery brought into contact with an outer periphery of said metal tube, in a radial direction of a frame having an axial core which is in parallel to the axial core of the metal tube;    a step of arranging said plurality of ring-shaped tools in such a manner that an axial core of each of the ring-shaped tools is in parallel to the axial core of the metal tube and an inner periphery is brought into contact with the outer periphery of said metal tube or is not brought into contact therewith, and a step of arranging so as to pinch the metal tube; and    a step of rotating said metal tube around the axial core or rotating the frame in which a plurality of ring-shaped tools are arranged, and moving the axial core of the ring-shaped tool away from the axial core of the metal tube while moving the metal tube or the frame, thereby reducing the diameter in the end portion of the metal tube.    
   
   
       2 . A molding method of reducing a diameter in an end portion of a metal tube according to  claim 1 , 
 wherein the method reduces the diameter in the end portion of said metal tube in a tapered shape having an axial core coinciding with the axial core of the metal tube, by previously bringing the axial core of said metal tube into line with the axial core of the frame.    
   
   
       3 . A molding method of reducing a diameter in an end portion of a metal tube according to  claim 1 , 
 wherein the method reduces the diameter in the end portion of said metal tube in a tapered shape having an axial core which is eccentric from the axial core of the metal tube, by previously make the axial core of said metal tube eccentric from the axial core of the frame.    
   
   
       4 . A molding method of reducing a diameter in an end portion of a metal tube according to  claim 1 , 
 wherein the method reduces the diameter in the end portion of the metal tube in a tapered shape having an axial core which is eccentric with respect to the axial core of the metal tube, by rotating said metal tube around the axial core or rotating the frame in which a plurality of ring-shaped tools are arranged, moving the metal tube or the frame in a direction in which the ring-shaped tools reach the end portion of the metal tube, and moving the axial core of the ring-shaped tools away from the axial core of the metal tube while moving the axial core of the metal tube away from the axial core of the frame in parallel.    
   
   
       5 . A molding method of reducing a diameter in an end portion of a metal tube while inclining at least a partial axial core of the end portion to be reduced in the diameter with respect to an axial core of the metal tube, at a time of reducing the diameter in the end portion of the metal tube, comprising the following steps: 
 a step of arranging a plurality of ring-shaped tools rotating in a state in which an inner periphery is brought into contact with an outer periphery of the metal tube, in a radial direction of a frame and structuring an axial core of said frame and the axial core of the metal tube in such a manner as to be relatively changeable;    a step of setting the axial core of said frame to a previously set angle with respect to the axial core of the metal tube and arranging said plurality of ring-shaped tools in such a manner that the inner periphery of each of the ring-shaped tools is brought into contact with the outer periphery of the metal tube or is not brought into contact therewith,    a step of arranging so as to pinch the metal tube in said plurality of ring-shaped tools, thereafter rotating said metal tube around the axial core or rotating the frame in which a plurality of ring-shaped tools are arranged, and moving the metal tube or the frame, and moving the axial core of the ring-shaped tool away from the axial core of the metal tube while relatively changing the axial core of the frame and the axial core of the metal tube or without changing, in the process of moving said metal tube or the frame, thereby reducing the diameter in the end portion of the metal tube.    
   
   
       6 . A molding method of reducing a diameter in an end portion of a metal tube according to  claim 5 , 
 wherein the method reduces the diameter in the end portion of said metal tube in a tapered shape having an axial core inclined with respect to the axial core of the metal tube, by previously bringing the axial core of said metal tube into line with the axial core of the frame, and relatively moving the axial core of the frame and the axial core of the metal tube in parallel in the process of moving the metal tube or the frame as well as rotating said metal tube around the axial core or rotating the frame in which a plurality of ring-shaped tools are arranged.    
   
   
       7 . A molding method of reducing a diameter in an end portion of a metal tube according to  claim 5 , 
 wherein the method reduces the diameter in the end portion of said metal tube in a tapered shape having an axial core inclined with respect to the axial core of the metal tube by previously inclining the axial core of the metal tube and the axial core of the frame relatively, and maintaining the incline between the axial core of the metal tube and the axial core of the frame in the process of moving the metal tube or the frame as well as rotating said metal tube around the axial core or rotating the frame in which a plurality of ring-shaped tools are arranged.    
   
   
       8 . A molding method of reducing a diameter in an end portion of a metal tube according to  claim 5 , 
 wherein the method reduces the diameter in the end portion of said metal tube in a tapered shape having an axial core inclined with respect to the axial core of the metal tube, by setting the axial core of the metal tube and the axial core of the frame to a previously set angle, and relatively changing the angle between the axial core of the metal tube and the axial core of the frame together with the movement of said metal tube or the frame, in the process of moving the metal tube or the frame as well as rotating said metal tube around the axial core or rotating the frame in which a plurality of ring-shaped tools are arranged.    
   
   
       9 . A molding apparatus for reducing a diameter in an end portion of a metal tube, comprising: 
 a plurality of ring-shaped tools rotating in a state in which an inner periphery is brought into contact with an outer periphery of the metal tube;    a frame arranging and holding said plurality of ring-shaped tools in a radial direction;    a tool moving member provided in said frame and moving the individual ring-shaped tool within a surface which is orthogonal to an axial core of each of the ring-shaped tools;    a drive member rotating said frame;    a grip member arranged so as to face to said frame and gripping the metal tube to be reduced in diameter in the end portion; and    a supply car mounting said grip member and structured such as to be movable in a direction of moving said grip member mounting said grip member close to or away from said frame, and an orthogonal direction to said direction.    
   
   
       10 . A molding apparatus for reducing a diameter in an end portion of a metal tube according to  claim 9 , 
 wherein the molding apparatus further comprises a revolving member provided in said frame or the grip member arranged so as to face to said frame and relatively changing the angle formed by the axial cores.    
   
   
       11 . A molding apparatus for reducing a diameter in an end portion of a metal tube according to  claim 9 , 
 wherein a plurality of ring-shaped tools held by said frame are arranged at a uniform angle around the axial core of said frame.    
   
   
       12 . A molding apparatus for reducing a diameter in an end portion of a metal tube according to  claim 11 , 
 wherein a plurality of ring-shaped tools held by said frame are arranged at positions facing at 180 degree.