Conduction heating apparatus and hot press forming apparatus having the same, and conduction heating method

Abstract

A conduction heating apparatus performs conduction heating while clamping a work to be hot press-formed by a clamping mechanism to apply tension to the work. The clamping mechanism has a stationary clamping member and a movable clamping member, a lifting up/down cylinder for the stationary clamping member and the movable clamping member, and tensioning cylinders that drive the movable clamping member along the planar direction of the work, and in conduction heating. The stationary clamping member clamps one side of the work and hold it, and the movable clamping member moves while holding the other side of the work according to thermal deformation of the work, which applies tension to the work corresponding to the thermal deformation of the work.

1 . A conduction heating apparatus that performs conduction heating onto a work to be hot press-formed while clamping the work by a clamping mechanism under application of tension to the work, wherein
 the clamping mechanism comprises:   a stationary clamping member which clamps one side of the work to freely hold the one side of the work, and is fixed in position or capable of being freely fixed in position along a predetermined direction, and   a movable clamping member which clamps the other side of the work to freely hold the other side of the work, and to freely move along the predetermined direction; and wherein   in conduction heating, the stationary clamping member holds the one side of the work at a fixed position, and the movable clamping member moves along the predetermined direction while holding the other side of the work according to a thermal deformation along the predetermined direction of the work to apply tension to the work.   
     
     
         2 . The conduction heating apparatus according to  claim 1 , wherein;
 the clamping mechanism comprises:   a lifting up/down direction driving mechanism that drives the stationary clamping member and the movable clamping member to freely lift up/down along a thickness direction of the work to clamp the work, and   a movable clamping member driving mechanism that drives the movable clamping member to freely move along the predetermined direction.   
     
     
         3 . The conduction heating apparatus according to  claim 1 , wherein the stationary clamping member and the movable clamping member respectively have pairs of upper and lower clamps facing each other along the thickness direction of the work to freely pinch the work. 
     
     
         4 . The conduction heating apparatus according to  claim 3 , wherein the lower clamps spaced from each other along the predetermined direction, among the pairs of upper and lower clamps which the stationary clamping member and the movable clamping member respectively have, are a pair of electrodes for energizing the work. 
     
     
         5 . The conduction heating apparatus according to  claim 3 , wherein portions of the upper clamps pinching the work are of convex curved shape, and portions of the lower clamps pinching the work are of planar shape. 
     
     
         6 . The conduction heating apparatus according to  claim 1 , comprising a droop preventing member which is disposed beneath a central portion of the work during conduction heating, the droop preventing member freely supports the central portion. 
     
     
         7 . The conduction heating apparatus according to  claim 6 , wherein the droop preventing member is a plurality of pins provided upright along the vertical direction. 
     
     
         8 . A conduction heating apparatus that performs conduction heating onto a work to be hot press-formed while clamping the work by a clamping mechanism under application of tension to the work, wherein
 the clamping mechanism comprises:   first and second clamping members that clamp the work at different clamping positions, respectively, to apply tension to the work;   a clamping direction driving mechanism driving the first and second clamping members to clamp the work; and   a clamping distance varying mechanism varying a clamping distance between the first and second clamping members according to a thermal deformation of the work upon conduction heating.   
     
     
         9 . A hot press forming apparatus comprising:
 the conduction heating apparatus according to any one of  claim 1 ; and   a hot press mechanism that hot press-forms the work heated by the conduction heating apparatus.   
     
     
         10 . A conduction heating method for performing conduction heating onto a work to be hot press-formed while clamping the work under application of tension to the work, the method comprising:
 clamping for applying tension to the work while clamping one side and the other side of the work, respectively, to hold the work;   conduction heating for performing conduction heating onto the clamped work; and   applying a tension in the conduction heating by clamping the one side of the work at a fixed position and moving the other clamping position of the work along with the work thermally deforming upon the conduction heating.   
     
     
         11 . The method according to  claim 10 , comprising:
 clamping one side of the work to freely hold the one side of the work, and at a fixed position in a predetermined direction;   clamping the other side of the work to freely hold the other side of the work, and to freely move along the predetermined direction; wherein;   in conduction heating, the one side of the work is clamped at a fixed position, and the movable clamped side moves along the predetermined direction while holding the other side of the work according to a thermal deformation along the predetermined direction of the work to apply tension to the work.   
     
     
         12 . The method according to  claim 10 , further comprising:
 driving the stationary clamping member and the movable clamping member so as to freely lift up/down along a thickness direction of the work to clamp the work; and   movably clamping the movable clamped side so as to freely move along the predetermined direction.   
     
     
         13 . The method according to  claim 10 , wherein the stationary clamping and the movable clamping respectively are performed by pairs of upper and lower clamps facing each other along the thickness direction of the work to freely pinch the work. 
     
     
         14 . The method according to  claim 13 , wherein the lower clamps spaced from each other along the predetermined direction, among the pairs of upper and lower clamps which the stationary clamping member and the movable clamping member respectively have, serve as a pair of electrodes for energizing the work. 
     
     
         15 . The method according to  claim 13 , wherein portions of the upper clamps pinching the work are of convex curved shape, and portions of the lower clamps pinching the work are of planar shape. 
     
     
         16 . The method according to  claim 10 , wherein a central portion is supported by a droop preventing member which is disposed beneath a central portion of the work during conduction heating, thereby preventing droop of the central portion of the work. 
     
     
         17 . The method according to  claim 16 , wherein the droop preventing member comprises a plurality of pins provided upright along the vertical direction. 
     
     
         18 . A hot press forming method comprising:
 the conduction heating method according to  claim 10 ; and   hot press-forming the work heated by the conduction heating to produce a hot-press-formed product.   
     
     
         19 . A hot press forming apparatus comprising:
 the conduction heating apparatus according to  claim 8 ; and   a hot press mechanism that hot press-forms the work heated by the conduction heating apparatus.