Hot press forming apparatus and hot press forming method

Abstract

During the press forming process of forming a blank sheet material while clamping a die on a punch, a trim portion is clamped between a trim holding step and a cut holder in such a state that elastic force of a spring mechanism is being applied on the trim portion. As a press forming operation by the die goes on, the trimming blade is relatively moved along an outer margin of a punch-side forming surface portion while the cut holder opposes elastic force of the spring mechanism by receiving pressing force of the trim holding step so that the trimming blade shears and cuts off the trim portion between the trimming blade and the tip end corner on the outer margin of the punch-side forming surface portion.

What is claimed is: 
     
         1 . A hot press forming apparatus comprising:
 a press forming apparatus configured to form a pre-heated blank sheet material into a shape of a press-formed work by clamping a die having a forming surface portion on a punch having a forming surface portion;   a trim portion cut-off apparatus configured to trim a trim portion as a margin being a portion of the blank sheet material that is not included in the press-formed work; and   a quench-hardening apparatus configured to quench and harden the heated blank sheet material by rapidly cooling while being clamped between the punch and the die, wherein   the trim portion cut-off apparatus has:   a trim holding step that is formed forward as to protrude toward the punch at an outer margin of the forming surface portion of the die;   a trimming tool that includes a trimming blade formed on a tip end corner on an inner margin of the trim holding step, and a tip end corner formed on an outer margin of the forming surface portion of the punch;   a cut holder that is arranged adjacent to the outer margin of the forming surface portion of the punch so as to face the trim holding step; and   a spring mechanism that is provided on the punch and that supports the cut holder in such a state that the cut holder is elastically energized toward the trim holding step, the cut holder being movable closer to/away from the trim holding step, wherein   during a press forming process of forming the blank sheet material while the press forming apparatus is clamping the die on the punch, the trim portion is clamped between the trim holding step and the cut holder in such a state that elastic force of the spring mechanism is being applied,   as a press forming operation by the die goes on, the trimming blade is relatively moved along the outer margin of the forming surface portion of the punch while the cut holder opposes elastic force of the spring mechanism by receiving pressing force of the trim holding step so that the trimming blade shears and cuts off the trim portion between the trimming blade and the tip end corner on the outer margin of the forming surface portion of the punch, and   after the cutting off process of the trim portion by the trim portion cut-off apparatus ends, the quench-hardening apparatus quenches the blank sheet material by clamping the blank sheet material between the punch and the die finally.   
     
     
         2 . A hot press forming method using a hot press forming apparatus, wherein
 the hot press forming apparatus has:   a press forming apparatus configured to form a pre-heated blank sheet material into a shape of a press-formed work by clamping a die having a forming surface portion on a punch having a forming surface portion;   a trim portion cut-off apparatus configured to trim a trim portion as a margin being a portion of the blank sheet material that is not included in the press-formed work; and   a quench-hardening apparatus configured to quench and harden the heated blank sheet material by rapidly cooling while being clamped between the punch and the die, wherein   the trim portion cut-off apparatus has:   a trim holding step that is formed forward so as to protrude toward the punch at an outer margin of the forming surface portion of the die;   a trimming tool that includes a trimming blade formed on a tip end corner on an inner margin of the trim holding step, and a tip end corner formed on an outer margin of the forming surface portion of the punch;   a cut holder that is arranged adjacent to the outer margin of the forming surface portion of the punch so as to face the trim holding step; and   a spring mechanism that is provided on the punch and that supports the cut holder in such a state that the cut holder is elastically energized toward the trim holding step, the cut holder being movable closer to/away from the trim holding step, and   the hot press forming method comprises:   during a press forming process of forming the blank sheet material while clamping the die on the punch by the press forming apparatus, clamping the trim portion between the trim holding step and the cut holder in such a state that elastic force of the spring mechanism is being applied;   as a press forming operation by the die goes on, shearing and cutting off, by the trimming blade, the trim portion between the trimming blade and the tip end corner on the outer margin of the forming surface portion of the punch by causing the trimming blade to relatively move along the outer margin of the forming surface portion of the punch while causing the cut holder to oppose elastic force of the spring mechanism by receiving pressing force of the trim holding step; and   after the cutting off process of the trim portion by the trim portion cut-off apparatus ends, quenching, by the quench-hardening apparatus, the blank sheet material by clamping the blank sheet material the punch and the die finally.