Press working method

Abstract

A press working mechanism has a punch and a die, which are arranged to be opposed to each other in a vertical direction. A work-piece is set at a position between the punch and the die, so that a press working force is applied by the punch to the work-piece. An upper-side surface of the die has a recessed portion, a shape of which corresponds to a shape of a final press working product. A lower-side surface of the punch has a center projected portion, a shape of which corresponds to the shape of the final press forming product, and an outside projected portion. The work-piece has a main portion and a predetermined first-contact portion. Specifications for a dimensional accuracy of a press work, which is required for the predetermined first-contact portion, is made to be lower than that required for the main portion. The outside projected portion of the punch and the die hold the predetermined first-contact portion of the work-piece prior to the main portion thereof in an initial stage of a press working process, so that a press work is done for the first-contact portion.

What is claimed is: 
     
         1 . In a press working apparatus, which comprises;
 a press working mechanism having a punch and a die, which are arranged at positions to be opposed to each other in order to hold a work-piece between the punch and the die and to apply a press working force to the work-piece so that the work-piece is deformed in a desired shape,   a press working method comprising;   a step for holding a predetermined first-contact portion of the work-piece prior to a main press-work portion of the work-piece in an initial stage of a press working process,   wherein at least one of specifications with respect to a dimensional accuracy of a press work, a mechanical strength and durability, which are required for the predetermined first-contact portion is made to be lower than that required for the main press-work portion of the work-piece.   
     
     
         2 . The press working method according to  claim 1 , wherein
 the predetermined first-contact portion of the work-piece corresponds to a cut-out portion, which is cut out after the press working process.   
     
     
         3 . The press working method according to  claim 1 , wherein
 one of the punch and the die is made of an elastic body, while the other of the punch and the die is made of a rigid body.   
     
     
         4 . The press working method according to  claim 3 , wherein
 the elastic body, of which one of the punch and the die is made, is composed of a hyper-elastic body having an incompressibility and a restoring characteristic, and   the hyper-elastic body includes rubber and urethane.   
     
     
         5 . The press working method according to  claim 3 , wherein
 a portion of the punch or the die, which is at first brought into contact with the predetermined first-contact portion of the work-piece, is more projected or convexed toward the work-piece than a remaining portion of the punch or the die.   
     
     
         6 . The press working method according to  claim 3 , wherein
 a portion of the punch or the die, which is made of the rigid body, is projected or convexed toward the work-piece, and   such a projected or convexed portion is brought into contact with the predetermined first-contact portion of the work-piece prior to the main press-work portion of the work-piece, so that the punch and the die hold the predetermined first-contact portion prior to the main press-work portion of the work-piece in the press working process.   
     
     
         7 . The press working method according to  claim 3 , wherein
 the punch or the die, which is made of the elastic body, has a thickness in a press working direction, and   the thickness of the elastic body is larger than a deformation size of the work-piece during the press working process.   
     
     
         8 . The press working method according to  claim 3 , wherein
 one of the punch and the die is made of the elastic body, which is composed of liquid including water and oil, and   a liquid pressure of the liquid is applied to the work-piece as the press working force.   
     
     
         9 . The press working method according to  claim 8 , wherein
 one of the punch and the die is made of the elastic body, which is composed or the liquid and applies the press working force to the work-piece,   the other of the punch and the die is made of the rigid body for receiving the press working force together with the work-piece,   a portion of the rigid body is projected or convexed toward the work-piece, and   such a projected or convexed portion is brought into contact with the predetermined first-contact portion of the work-piece prior to the main press-work portion of the work-piece, so that the punch and the die hold the predetermined first-contact portion prior to the main press-work portion of the work-piece in the press working process.   
     
     
         10 . The press working method according to  claim 1 , wherein
 the work-piece is made of a flat-plate type thin metal material or a band-like thin metal material.   
     
     
         11 . The press working method according to  claim 10 , wherein
 the work-piece is made of the band-like thin metal material wound in a roll shape, and   the band-like thin metal material is continuously transferred by a transport mechanism to the press working mechanism.   
     
     
         12 . A press working apparatus comprising;
 a press working mechanism having a punch and a die, which are arranged at positions to be opposed to each other in order to hold a work-piece between the punch and the die and to apply a press working force to the work-piece so that the work-piece is deformed in a desired shape,   wherein the punch and the die holds a predetermined first-contact portion of the work-piece prior to a main press-work portion of the work-piece, in an initial stage of a press working process,   wherein at least one of specifications with respect to a dimensional accuracy of a press work, a mechanical strength and durability, which are required for the predetermined first-contact portion is made to be lower than that required for the main press-work portion of the work-piece.   
     
     
         13 . The press working apparatus according to  claim 12 , wherein
 the predetermined first-contact portion of the work-piece corresponds to a cut-out portion, which is cut out after the press working process.   
     
     
         14 . The press working apparatus according to  claim 12 , wherein
 one of the punch and the die is made of an elastic body, while the other of the punch and the die is made of a rigid body.   
     
     
         15 . The press working apparatus according to  claim 14 , wherein
 the elastic body, of which one of the punch and the die is made, is composed of a hyper-elastic body having an incompressibility and a restoring characteristic, and   the hyper-elastic body includes rubber and urethane.   
     
     
         16 . The press working apparatus according to  claim 14 , wherein
 a portion of the punch or the die, which is at first brought into contact with the predetermined first-contact portion of the work-piece, is more projected or convexed toward the work-piece than a remaining portion of the punch or the die.   
     
     
         17 . The press working apparatus according to  claim 14 , wherein
 a portion of the punch or the die, which is made of the rigid body, is projected or convexed toward the work-piece, and   such a projected or convexed portion is brought into contact with the predetermined first-contact portion of the work-piece prior to the main press-work portion of the work-piece, so that the punch and the die hold the predetermined first-contact portion prior to the main press-work portion of the work-piece in the press working process.   
     
     
         18 . The press working apparatus according to  claim 14 , wherein
 the punch or the die, which is made of the elastic body, has a thickness in a press working direction, and   the thickness of the elastic body is larger than a deformation size of the work-piece during the press working process.   
     
     
         19 . The press working apparatus according to  claim 14 , wherein
 one of the punch and the die is made of the elastic body, which is composed of liquid including water and oil, and   a liquid pressure of the liquid is applied to the work-piece as the press working force.   
     
     
         20 . The press working apparatus according to  claim 19 , wherein
 one of the punch and the die is made of the elastic body, which is composed of the liquid and applies the press working force to the work-piece,   the other of the punch and the die is made of the rigid body for receiving the press working force together with the work-piece,   a portion of the rigid body is projected or convexed toward the work-piece, and   such a projected or convexed portion is brought into contact with the predetermined first-contact portion of the work-piece prior to the main press-work portion of the work-piece, so that the punch and the die hold the predetermined first-contact portion prior to the main press-work portion of the work-piece in the press working process.   
     
     
         21 . The press working apparatus according to  claim 12 , wherein
 the work-piece is made of a flat-plate type thin metal material or a band-like thin metal material.   
     
     
         22 . The press working apparatus according to  claim 21 , wherein
 the work-piece is made of the band-like thin metal material wound in a roll shape, and   the band-like thin metal material is continuously transferred by a transport mechanism to the press working mechanism.   
     
     
         23 . A press working product comprises;
 a product manufactured by the press working method according to  claim 1 .   
     
     
         24 . The press working product according to  claim 23 , wherein
 the press working product is a metal diaphragm,   a surface rigidity of the metal diaphragm after the press working process is higher than that of the work-piece before the press working process in the press working direction.   
     
     
         25 . The press working product according to  claim 24 , wherein
 the metal diaphragm is applied to one of the following products;
 a pressure sensor; 
 a pressure measuring device; 
 an air-tightness holding device including a sealing part; 
 a hermetic seal; 
 a metal part including a heat radiating part; and 
 a product including a part of spring material. 
   
     
     
         26 . The press working product according to  claim 23 , wherein
 the press working product is made of one of the following materials;
 a metal material; 
 a natural resin; 
 a synthetic resin including carbonaceous resin; 
 a fiber material; 
 a paper material: and 
 a wood. 
   
     
     
         27 . In a press working product,
 the press working product comprises a metal diaphragm made of a thin plate material and having a center recessed portion and an outside recessed portion of an annular shape, wherein the outside recessed portion surrounds the center recessed portion so as to be concentric with the center recessed portion, and   the press working product is manufactured by a press working mechanism, which comprises a punch and a die so arranged as to be opposed to each other in a vertical direction, wherein the punch is movable with respect to the die in order to carry out a press work to a work-piece which is set between the punch and the die, and wherein the punch has a center projected portion and an outside projected portion each of which is projected in a direction to the die,   a press working process comprising;   a first step for moving down the punch of the press working mechanism to the die in order that the outside projected portion is at first brought into contact with a predetermined first-contact portion of the work-piece prior to a center portion of the work-piece, so that the first-contact portion of the work-piece is partly or fully deformed by a downward movement of the punch in order to move a part of work-piece material from the first-contact portion in a direction to the center portion; and   a second step for further moving down the punch to the die so that the center projected portion is brought into contact with the center portion of the work-piece in order to carry out the press work to the center portion.