Die for press working

Abstract

A die for press working includes a punch part and a die part. The outer peripheral surface and tip surface of the punch part and the inner peripheral surface of the die part are coated with carbon films having a surface roughness Ra of 0.05 μm or lower. An intra-punch refrigerant flow channel in the punch part allows a cooling medium to flow. An intra-die refrigerant flow channel in the die part allows the cooling medium to flow. The intra-punch refrigerant flow channel has a central flow channel portion where a tip on the central axis of the punch part is disposed at a tip of the punch part. Radial flow channel portions have base ends connected to the tip of the central flow channel portion, extending radially at mutually equiangular intervals. Outer peripheral flow channel portions have base ends connected to the tips of the radial flow channel portions.

1 . A die for press working comprising:
 a punch part;   a die part;   an intra-punch refrigerant flow channel provided inside the punch part; and   an intra-die refrigerant flow channel provided inside the die part, wherein   the punch part and the die part perform a forming process on a workpiece,   an outer peripheral surface and a tip surface of the punch part and an inner peripheral surface of the die part are coated with carbon films having a surface roughness Ra of 0.05 μm or lower,   the intra-punch refrigerant flow channel allows a cooling medium to flow therethrough,   the intra-die refrigerant flow channel allows the cooling medium to flow therethrough,   the punch part has a columnar shape, and   the intra-punch refrigerant flow channel includes:   a central flow channel portion where a tip formed on the central axis of the punch part is disposed at a tip portion of the punch part;   a plurality of radial flow channel portions that have base ends connected to the tip of the central flow channel portion, said radial flow channel portions extending radially at mutually equiangular intervals; and   a plurality of outer peripheral flow channel portions that have base ends connected to the tips of the radial flow channel portions and are provided along the central axis in a vicinity of the outer peripheral surface of the punch part.   
     
     
         2 . The die for press working according to  claim 1 ,
 wherein the die part has an annular shape, and the intra-die refrigerant flow channel has an annular shape disposed along the circumferential direction of the die part.   
     
     
         3 . The die for press working according to  claim 1 , further comprising:
 a refrigerant supply source that supplies the cooling medium into the intra-punch refrigerant flow channel and the intra-die refrigerant flow channel,   wherein the refrigerant supply source causes the cooling medium to flow with turbulence where the Reynolds number of the flow is equal to or higher than 3000, the cooling medium traveling through the inside of the intra-punch refrigerant flow channel and the inside of the intra-die refrigerant flow channel.   
     
     
         4 . The die for press working according to  claim 1 , further comprising:
 a refrigerant supply source that supplies the cooling medium into the intra-punch refrigerant flow channel and the intra-die refrigerant flow channel,   wherein the refrigerant supply source controls the temperature of the carbon films to be lower than 300° by controlling a flow of the cooling medium.   
     
     
         5 . The die for press working according to  claim 1 ,
 wherein the punch part includes:   a bottomed cylindrical outside substrate that has the carbon films provided on the outer peripheral surface and tip surface thereof and is made of cemented carbide, and   an inside substrate that is provided inside the outside substrate, has the intra-punch refrigerant flow channel formed therein, and is made of copper or a copper alloy.   
     
     
         6 . The die for press working according to  claim 1 ,
 wherein the workpiece is an aluminum alloy thin sheet, and   wherein the die for press working is a die for dry press working that performs drawing and ironing on the aluminum alloy thin sheet   
     
     
         7 . The die for press working according to  claim 2 , further comprising:
 a refrigerant supply source that supplies the cooling medium into the intra-punch refrigerant flow channel and the intra-die refrigerant flow channel,   wherein the refrigerant supply source causes the cooling medium to flow with turbulence where the Reynolds number of the flow is equal to or higher than  3000 , the cooling medium traveling through the inside of the intra-punch refrigerant flow channel and the inside of the intra-die refrigerant flow channel.   
     
     
         8 . The die for press working according to  claim 2 , further comprising:
 a refrigerant supply source that supplies the cooling medium into the intra-punch refrigerant flow channel and the intra-die refrigerant flow channel,   wherein the refrigerant supply source controls the temperature of the carbon films to be lower than 300° by controlling a flow of the cooling medium.   
     
     
         9 . The die for press working according to  claim 3 , further comprising:
 a refrigerant supply source that supplies the-cooling medium into the intra-punch refrigerant flow channel and the intra-die refrigerant flow channel,   wherein the refrigerant supply source controls the temperature of the carbon films to be lower than 300° by controlling a flow of the cooling medium.   
     
     
         10 . The die for press working according to  claim 2 ,
 wherein the punch part includes:   a bottomed cylindrical outside substrate that has the carbon films provided on the outer peripheral surface and tip surface thereof and is made of cemented carbide, and   an inside substrate that is provided inside the outside substrate, has the intra-punch refrigerant flow channel formed therein, and is made of copper or a copper alloy.   
     
     
         11 . The die for press working according to  claim 3 ,
 wherein the punch part includes:   a bottomed cylindrical outside substrate that has the carbon films provided on the outer peripheral surface and tip surface thereof and is made of cemented carbide, and   an inside substrate that is provided inside the outside substrate, has the intra-punch refrigerant flow channel formed therein, and is made of copper or a copper alloy.   
     
     
         12 . The die for press working according to  claim 4 ,
 wherein the punch part includes:   a bottomed cylindrical outside substrate that has the carbon films provided on the outer peripheral surface and tip surface thereof and is made of cemented carbide, and   an inside substrate that is provided inside the outside substrate, has the intra-punch refrigerant flow channel formed therein, and is made of copper or a copper alloy.   
     
     
         13 . The die for press working according to  claim 2 ,
 wherein the workpiece is an aluminum alloy thin sheet, and   wherein the die for press working is a die for dry press working that performs drawing and ironing on the aluminum alloy thin sheet.   
     
     
         14 . The die for press working according to  claim 3 ,
 wherein the workpiece is an aluminum alloy thin sheet, and   wherein the die for press working is a die for dry press working that performs drawing and ironing on the aluminum alloy thin sheet.   
     
     
         15 . The die for press working according to  claim 4 ,
 wherein the workpiece is an aluminum alloy thin sheet, and   wherein the die for press working is a die for dry press working that performs drawing and ironing on the aluminum alloy thin sheet.   
     
     
         16 . The die for press working according to  claim 5 ,
 wherein the workpiece is an aluminum alloy thin sheet, and   wherein the die for press working is a die for dry press working that performs drawing and ironing on the aluminum alloy thin sheet.