Assist drawing device

Abstract

Provided is an assist drawing device by which, when a punch is moved from a stroke start edge toward a stroke end edge in accordance with a command from a control device to a punch drive unit, and drawing is performed in cooperation with a drawing die to thereby perform the drawing, assist drawing is performed while pressing a blank material against the drawing die by a blank holder and pressing both end surfaces of the blank material by assist punches, and in which the control device includes an assist pressure control unit configured to control an assist punch drive unit such that, when the assist drawing is performed, an assist pressure of the assist punches reaches a target assist pressure in accordance with a position of the punch.

What is claimed is: 
     
         1 . An assist drawing device, comprising:
 a punch, which has a shape conforming to a product shape, and is configured to be linearly reciprocated between a stroke start edge and a stroke end edge;   a drawing die, which has an opening conforming to the product shape, and is configured to perform drawing on a blank material having a plate shape in cooperation with the punch;   a blank holder configured to press the blank material against the drawing die at a blank holder pressure;   a pair of assist punches, which are movably inserted between the drawing die and the blank holder, and are arranged opposed to each other so as to be capable of pressing end surfaces of the blank material from opposing directions at an assist pressure;   a punch drive unit configured to drive the punch; and   an assist punch drive unit configured to supply the assist pressure to the pair of assist punches,   wherein, when the punch is moved from the stroke start edge toward the stroke end edge in accordance with a command from the control device to the punch drive unit, and drawing is performed in cooperation with the drawing die, assist drawing is performed while pressing the blank material against the drawing die by the blank holder and pressing both end surfaces of the blank material by the pair of assist punches, and   wherein the control device includes an assist pressure control unit configured to control the assist punch drive unit such that, when the assist drawing is performed, the assist pressure of the pair of assist punches reaches a target assist pressure in accordance with a position of the punch.   
     
     
         2 . The assist drawing device according to  claim 1 , further comprising punch position information acquisition unit configured to acquire position information on the punch,
 wherein the assist pressure control unit is configured to control, based on the actual position information on the punch acquired by the punch position information acquisition unit, the assist punch drive unit such that the assist pressure of the pair of assist punches reaches the target assist pressure in accordance with the position of the punch.   
     
     
         3 . The assist drawing device according to  claim 1 , further comprising assist pressure information acquisition unit configured to acquire assist pressure information on the pair of assist punches,
 wherein the assist pressure control unit is configured to control, based on the actual assist pressure information acquired by the assist pressure information acquisition unit, the assist punch drive unit such that the assist pressure of the pair of assist punches reaches the target assist pressure in accordance with the position of the punch.   
     
     
         4 . The assist drawing device according to  claim 2 , further comprising assist pressure information acquisition unit configured to acquire assist pressure information on the pair of assist punches,
 wherein the assist pressure control unit is configured to control, based on the actual assist pressure information acquired by the assist pressure information acquisition unit, the assist punch drive unit such that the assist pressure of the pair of assist punches reaches the target assist pressure in accordance with the position of the punch.   
     
     
         5 . The assist drawing device according to  claim 1 ,
 wherein the control device is configured to use the command to the punch drive unit to move the punch from a current position, and   wherein the assist pressure control unit is configured to:
 set the target assist pressure in accordance with the position of the punch to the target assist pressure at a position after the movement from the current position of the punch in accordance with the command from the control device to the punch drive unit; and 
 execute pressure synchronization control of changing the target assist pressure in accordance with the position of the punch from the target assist pressure at the current position of the punch to the target assist pressure at the position after the movement. 
   
     
     
         6 . The assist drawing device according to  claim 2 ,
 wherein the control device is configured to use the command to the punch drive unit to move the punch from a current position, and   wherein the assist pressure control unit is configured to:
 set the target assist pressure in accordance with the position of the punch to the target assist pressure at a position after the movement from the current position of the punch in accordance with the command from the control device to the punch drive unit; and 
 execute pressure synchronization control of changing the target assist pressure in accordance with the position of the punch from the target assist pressure at the current position of the punch to the target assist pressure at the position after the movement. 
   
     
     
         7 . The assist drawing device according to  claim 3 ,
 wherein the control device is configured to use the command to the punch drive unit to move the punch from a current position, and   wherein the assist pressure control unit is configured to:
 set the target assist pressure in accordance with the position of the punch to the target assist pressure at a position after the movement from the current position of the punch in accordance with the command from the control device to the punch drive unit; and 
 execute pressure synchronization control of changing the target assist pressure in accordance with the position of the punch from the target assist pressure at the current position of the punch to the target assist pressure at the position after the movement. 
   
     
     
         8 . The assist drawing device according to  claim 4 ,
 wherein the control device is configured to use the command to the punch drive unit to move the punch from a current position, and   wherein the assist pressure control unit is configured to:
 set the target assist pressure in accordance with the position of the punch to the target assist pressure at a position after the movement from the current position of the punch in accordance with the command from the control device to the punch drive unit; and 
 execute pressure synchronization control of changing the target assist pressure in accordance with the position of the punch from the target assist pressure at the current position of the punch to the target assist pressure at the position after the movement. 
   
     
     
         9 . The assist drawing device according to  claim 1 , further comprising:
 a blank holder drive unit configured to supply a blank holder pressure to the blank holder;   a cushion pad configured to press the blank material at a cushion pressure from a direction opposing the movement of the punch when the assist drawing is performed; and   a cushion pad drive unit configured to supply the cushion pressure to the cushion pad, wherein the control device is configured to control at least one of the blank holder drive unit or the cushion pad drive unit such that, when the assist drawing is performed, at least one of the blank holder pressure or the cushion pressure reaches a target blank holder pressure or a target cushion pressure in accordance with the position of the punch.