Hot-press device

Abstract

A hot press device (1) uses an upper pressure-holding surface (41a) and a lower pressure-holding surface (42a) of an upper cooling die (41) and a lower cooling die (42) in a cooling die set (40) to hold under pressure and cool a primary formed product (P) that is obtained in a forming area (3) and is in a high temperature state, so that a hardened vehicle frame (F) is obtained. The lower cooling die (42) includes a first liquid reservoir (44) for retaining liquid coolant.

1 . A hot press device configured such that a primary formed product that is obtained in a forming area and is in a high temperature state is held under pressure and cooled on respective pressure holding surfaces of an upper die and a lower die in a cooling die set to thereby obtain a hardened final formed product,
 wherein the lower die includes a liquid reservoir for retaining liquid coolant.   
     
     
         2 . The hot press device according to  claim 1 , wherein at least one of the upper die or the lower die includes a liquid supply portion for depositing the liquid coolant on the primary formed product held under pressure, and
 a first liquid reservoir is provided in the lower die as the liquid reservoir, the first liquid reservoir configured to collect and retain the liquid coolant deposited from the liquid supply portion on the primary formed product.   
     
     
         3 . The hot press device according to  claim 2 , wherein the first liquid reservoir includes a cooling opening that is open at the pressure-holding surface of the lower die for the primary formed product, and
 the liquid supply portion includes a jetting nozzle disposed in the first liquid reservoir, and is configured such that the liquid coolant jetted from the jetting nozzle is sprayed via the cooling opening onto the primary formed product held under pressure, or that compressed air jetted from within the liquid coolant retained in the first liquid reservoir by the jetting nozzle passes through a surface of the liquid coolant so that the liquid coolant is scattered and sprayed via the cooling opening onto the primary formed product held under pressure.   
     
     
         4 . The hot press device according to  claim 2 , wherein the upper die includes a cooling recess that is open at the pressure-holding surface of the upper die for the primary formed product, and
 the liquid supply portion is capable of supplying the liquid coolant to the cooling recess.   
     
     
         5 . The hot press device according to  claim 4 , wherein the cooling recess is provided at a location corresponding to the pressure-holding surface of the lower die, and
 the first liquid reservoir is provided at a location corresponding to the pressure-holding surface of the upper die.   
     
     
         6 . The hot press device according to  claim 4 , wherein a plurality of upper cooling grooves are formed in the pressure-holding surface of the upper die, the upper cooling grooves each having an end portion that is open to the cooling recess. 
     
     
         7 . The hot press device according to  claim 2 , wherein a plurality of lower cooling grooves are formed in the pressure-holding surface of the lower die, the lower cooling grooves each having an end portion that is open to the first liquid reservoir. 
     
     
         8 . The hot press device according to  claim 7 , wherein a second liquid reservoir is provided in an outer region of the first liquid reservoir of the lower die as the liquid reservoir, the second liquid reservoir extending to surround the first liquid reservoir and being capable of retaining the liquid coolant, and
 the second liquid reservoir is configured such that when an amount of the liquid medium retained in the first liquid reservoir increases, the liquid coolant moves via the lower cooling grooves to the second liquid reservoir and is retained in the second liquid reservoir.   
     
     
         9 . The hot press device according to  claim 1 , wherein a third liquid reservoir is provided in the lower die as the liquid reservoir, the third liquid reservoir being open upward and capable of retaining the liquid coolant, and the pressure-holding surface of the lower die located on an inner side of the third liquid reservoir, and
 an outer wall of the third liquid reservoir includes a volume varying wall, the volume varying wall including an upper end provided at a level higher than the pressure-holding surface of the lower die, and the volume varying wall configured to move in a horizontal direction to vary a retaining volume of the third liquid reservoir.   
     
     
         10 . The hot press device according to  claim 9 , wherein the volume varying wall is configured to move toward or away from the pressure-holding surface of the lower die to vary the retaining volume of the third liquid reservoir. 
     
     
         11 . The hot press device according to  claim 10 , wherein a lower sloping surface is formed on a side of the volume varying wall opposite the third liquid reservoir, the lower sloping surface inclined to extend progressively away from the third liquid reservoir toward a lower portion, and
 an upper sloping surface is formed at a location of the upper die corresponding to the volume varying wall, the upper sloping surface inclined to correspond to the lower sloping surface, and configured such that when the upper die is moved downward with respect to the lower die, the upper sloping surface makes sliding contact with the lower sloping surface to press the volume varying wall toward a pressure-holding surface side of the lower die to move the volume varying wall toward the pressure-holding surface of the lower die.   
     
     
         12 . The hot press device according to  claim 9 , wherein a recess that is open upward is provided in the pressure-holding surface of the lower die as the liquid reservoir. 
     
     
         13 . The hot press device according to  claim 12 , wherein a communication passage is formed in the lower die, the communication passage configured to provide communication of an inner space of the recess with the third liquid reservoir. 
     
     
         14 . The hot press device according to  claim 1 , wherein the lower die includes a lower recess as the liquid reservoir, a first cylinder portion, and a first communication passage, the lower recess being open at a location corresponding to the pressure-holding surface of the lower die, the first cylinder portion including a first cylinder chamber in which a first piston is housed such that the first piston is reciprocally movable, and the first communication passage configured to provide communication of the first cylinder chamber with the lower recess, and
 a first reservoir chamber is provided in the first cylinder chamber as the liquid reservoir, the first reservoir chamber bounded by the first piston, associated with the first communication passage, and configured to retain the liquid coolant.   
     
     
         15 . The hot press device according to  claim 14 , wherein the first cylinder chamber is open upward,
 the first piston is configured to be reciprocally movable in a vertical direction,   the first reservoir chamber is located under the first piston, and   a first pressing portion is provided at a location of the upper die corresponding to the first piston, the first pressing portion configured to push the first piston downward as the upper die is moved downward.   
     
     
         16 . The hot press device according to  claim 14 , wherein the upper die includes an upper recess, a second cylinder portion, and a second communication passage, the upper recess being open at a location corresponding to the pressure-holding surface of the upper die, the second cylinder portion including a second cylinder chamber in which a second piston is housed such that the second piston is reciprocally movable, and the second communication passage configured to provide communication of the second cylinder chamber with the upper recess, and
 a second reservoir chamber is formed in the second cylinder chamber, the second reservoir chamber bounded by the second piston, associated with the second communication passage, and configured to retain the liquid coolant.   
     
     
         17 . The hot press device according to  claim 16 , wherein the second cylinder chamber is open downward,
 the second piston is configured to be reciprocally movable in a vertical direction,   the second reservoir chamber is located over the second piston, and   a second pressing portion is provided at a location of the lower die corresponding to the second piston, the second pressing portion configured push the second piston upward as the upper die is moved downward.   
     
     
         18 . The hot press device according to  claim 17 , wherein the first pressing portion includes a lower end portion of the second piston, and
 the second pressing portion includes an upper end portion of the first piston.   
     
     
         19 . The hot press device according to  claim 18 , wherein a first biasing member is provided in the first reservoir chamber, the first biasing member configured to press the first piston in a direction in which a retaining volume of the first reservoir chamber increases,
 a second biasing member is provided in the second reservoir chamber, the second biasing member configured to press the second piston in a direction in which a retaining volume of the second reservoir chamber increases, and   the first biasing member has smaller biasing force than the second biasing member.   
     
     
         20 . he hot press device according to  claim 19 , wherein a fourth liquid reservoir capable of retaining the liquid coolant is further included, and
 a third communication passage is formed in the upper die, the third communication passage configured to provide communication of the second reservoir chamber with the fourth liquid reservoir.