JP4616737B2 - Hot press molding die, hot press molding apparatus, and hot press molding method - Google Patents

Description

  The present invention relates to a hot press molding die, a hot press molding apparatus, and a hot press molding method, and is particularly suitable for deep drawing molding in which material flow accompanying a molding process is intense, and draw molding and curvature are severe. The present invention relates to a hot press molding die that enables foam molding, a hot press molding apparatus, and a hot press molding method.

Metal sheet press molding is highly productive, excellent in dimensional accuracy, and stable in quality with little variation in strength between pressed products, making it suitable for manufacturing automobiles, machinery, electrical equipment, transportation equipment, etc. It is the most common processing method widely used.
However, press products in recent years, especially automobile parts, are required to have high strength from the viewpoint of weight reduction, etc., and this leads to a decrease in formability, particularly a decrease in shape freezing due to the occurrence of a springback, It has become difficult to manufacture a press product having a complicated shape.

  For this reason, in the press industry of a metal plate material, hot press forming technology for forming a heated metal plate material using a mold is attracting attention. Hot press molding is press-molded with the metal plate heated to a high temperature, so the metal plate with reduced material strength deforms straight along the molding surface of the mold and is excellent even in complex shapes. Can be molded with high dimensional accuracy. Moreover, since it cools rapidly after shaping | molding by the die heat removal effect, a spring bag does not generate | occur | produce, it is excellent in shape freezing property, and can improve the dimensional accuracy of a press product. Further, when the metal plate material is steel, the steel plate is heated to the austenite region, and is retained in the mold by, for example, a predetermined cooling process, and rapidly cooled by the mold contact heat removal effect. Strengthening can be achieved.

  However, in the hot press forming in which the metal plate material is heated to a high temperature to perform press forming, as shown in FIG. 1, once the elongation due to forming occurs, the cross-sectional area of the portion becomes small. The intensity of the area where the decrease is reduced. For this reason, when press molding with intense material flow accompanying molding processing represented by deep drawing is performed, local thinning or breakage occurs in the stretched portion, and so-called draw molding cannot be performed. There was a problem. Further, even in the foam molding in which the material flow accompanying the processing is not intense as compared with the deep drawing molding, there is a problem that the fracture occurs in the molding processing with a severe curvature.

For this reason, in order to prevent breakage and cracks that occur during forming, when steel sheets are hot drawn using a punch and die, the steel sheet is temporarily held in proximity to the punch and die prior to forming. Then, a hot drawing forming method of a steel sheet that starts forming is proposed (for example, see Patent Document 1).
However, in this method, it is necessary to temporarily hold the steel plate prior to press forming, so that the forming time becomes long, and there is a problem that high productivity, which is a feature of press forming, is hindered. In particular, as the plate thickness is thicker, the holding time needs to be longer, so the productivity is greatly reduced.
Japanese Patent Laid-Open No. 2005-014002 JP 10-259392 A

  The problem to be solved by the present invention is a hot press that enables draw molding and form molding with severe curvature, which could not be realized by conventional hot press molding technology, while maintaining the high productivity characteristic of press molding. It is to provide a molding die, a hot press molding apparatus, and a hot press molding method.

  In order to prevent local metal thinning and breakage of the metal plate material to be molded as shown in FIG. 1, the present inventor is responsible for thinning and breakage caused by draw molding and foam molding with severe curvature, as well as these factors. As a result of many theoretical and experimental studies on how to solve the problem, the following technical findings were obtained.

(A) First, in the field of high-temperature plastic working such as hot pressing, a high-temperature plastic working lubricant such as a solid lubricant is used to protect the tool, and exhibits a certain effect ( For example, refer to Patent Document 2), and the use of a predetermined solid lubricant is effective in improving moldability of draw molding or foam molding with severe curvature.
(B) However, when the solid lubricant exerts its lubricating effect only after being fixed to the molding surface of the mold, the operator applies the solid lubricant to the mold and fixes it every time the press molding is performed. , Work time increases, productivity is greatly reduced. In addition, in order to shorten the working time, applying a solid lubricant to a metal plate material in advance, and trying to fix it by heating, the solid lubricant and binder are decomposed, and the function of the solid lubricant is reduced. It can't be done. Furthermore, in the method of mixing the solid lubricant with the refrigerant, the solid lubricant is washed away by the refrigerant and cannot function as a solid lubricant.
(C) However, before starting the press molding, more specifically, in the stage where the metal plate material is set between the molds and positioned, the heated metal plate material is still in a high temperature state. When a lubricating liquid in which a solid lubricant is dispersed or dissolved is discharged to a portion of a metal plate material having a high degree of processing, the solid lubricant contained in the lubricating liquid can be fixed to the metal plate material very easily.
(D) That is, the heated metal plate material is set between the upper die and the lower die, positioning is performed, and then the portion of the metal plate material having a high degree of processing, that is, the severely sliding portion between the metal plate material and the mold, Without discharging the lubricating liquid in which the solid lubricant is dispersed or dissolved, and fixing the solid lubricant contained in the lubricating liquid and then starting hot press molding including stretching, without hindering productivity, The lubrication effect by the solid lubricant, that is, the deformation concentration and frictional heat generation in the part with high workability can be avoided, which can prevent the local thinning, breakage and scratch of the metal plate material. Improved formability.

(E) Furthermore, not only the solid lubricant fixing process in the stage before the start of press molding as described above, but also the sliding portion between the mold and the metal plate during press molding from the start of molding to the completion of molding. The draw moldability can be further improved by supplying a predetermined solid lubricant. That is, it is possible to avoid deformation concentration and frictional heat generation in a sliding part having a high degree of processing, thereby preventing local metal thinning, breakage, and generation of scratches due to forming.

(F) However, since the lubrication effect of the solid lubricant disappears due to the consumption of the solid lubricant, in order to perform draw molding while maintaining high productivity, which is a feature of press molding, from the start of molding. Even during press molding up to the completion of molding, a solid lubricant can be easily supplied to the sliding portion between the mold and the metal plate material, particularly to the sliding portion having a high degree of processing that tends to cause thinning or breakage. It is desirable to provide means.

(G) And, as a means for supplying the solid lubricant to the sliding portion between the mold and the metal plate, a plurality of lubricating liquid supply ports are formed on the molding surface of the mold in consideration of productivity and controllability. It is desirable to supply a lubricating liquid in which a solid lubricant is dispersed or dissolved in a predetermined liquid from the formed lubricating liquid supply port. In addition, when the solid lubricant is dispersed or dissolved in a predetermined liquid, the solid lubricant easily flows into the sliding portion between the mold and the metal plate material, so that the lubricating effect of the solid lubricant is easily exhibited.

(H) Although the position of the sliding portion between the mold and the metal plate material, particularly the sliding portion having a high degree of processing, changes in accordance with the progress of press molding, for example, the amount of punch pressing, it communicates with the lubricating liquid supply port. By controlling a predetermined valve mechanism provided in the lubricating liquid supply pipe, the lubricating liquid can be supplied even to a sliding portion whose position changes as the press molding progresses. In addition, as described above, the position of the sliding portion between the metal mold and the metal plate changes according to the punch push-in amount, so the control of the valve mechanism, that is, the lubricant supply timing is controlled in synchronization with the punch push-in amount. It is desirable. Accordingly, a mold provided with a plurality of lubricating liquid supply ports on the molding surface of the mold described above, and a lubricating liquid supply pipe provided with a predetermined valve mechanism, which is a pipe communicating with the lubricating liquid supply port inside the mold. It is preferable that a predetermined control device for controlling a predetermined valve mechanism provided in the mold to control the supply of the lubricating liquid to each lubricating liquid supply pipe is connected and attached.

(I) Furthermore, since the solid lubricant exhibits a lubricating effect only after being fixed to the molding surface of the mold, the binder (binder component) is dispersed or dissolved in a predetermined liquid in which the solid lubricant is dispersed or dissolved. It is desirable. Similarly, it is desirable to provide a heating means for promoting the fixation of the solid lubricant inside the mold.

(J) Next, as for the cause of thinning and breakage of the metal plate due to forming, the deformation resistance of the stretched portion is improved by work hardening in the cold press, but the metal plate is heated to a high temperature in the hot press. Therefore, the deformation resistance of the metal plate material is low and the work hardening is small. For this reason, as shown in FIG. 1, once the elongation associated with the molding occurs, the cross-sectional area of the portion becomes smaller, so that the deformation resistance of the portion A where the plate thickness decreases due to the elongation becomes even lower. The portion A is broken.

(K) However, if the deformation resistance of the portion A can be forcibly increased by forcibly lowering the temperature of the portion A where the plate thickness decreases due to the elongation associated with the molding, as shown in FIG. Since the other part B whose deformation resistance is lower than A extends, the load on the part A can be reduced, and the thinning and breakage of the part A can be prevented.

(L) Further, the position of the portion A where the plate thickness decreases due to elongation can be specified by an experiment performed in advance. Therefore, as shown in FIG. 2, by forcibly lowering the temperature of the portion A where the thickness decreases due to elongation and forcibly increasing the deformation resistance of the portion A, the deformation resistance is relatively higher than that of the portion A. The other part B having a lower height is stretched, and the part B whose thickness is reduced due to the elongation is newly forced to increase the deformation resistance, and is deformed relative to the part B. By repeating the operation of extending the other part C having low resistance one after another, the part having low deformation resistance is successively extended without causing local thinning or breakage of the metal plate material to be formed. What can be done. In other words, draw molding by hot pressing and form molding with severe curvature are possible.

(M) In addition, the above knowledge is a method of forcibly increasing the deformation resistance of a portion where the plate thickness decreases due to elongation accompanying forming and extending another portion having a relatively lower deformation resistance than that portion. However, on the contrary, if the deformation resistance of the portion that does not need to be stretched due to molding, that is, the portion that does not want to cause elongation, is forcibly increased in advance, the deformation resistance is relatively higher than that portion. It is possible to stretch other parts of low. That is, as shown in FIG. 3, the deformation resistance of the portion D that is not desired to be stretched is forcibly increased in advance, and another portion E having a relatively lower deformation resistance than the portion D is extended, As a result, the deformation E is forcibly increased for the portion E where the plate thickness is reduced due to elongation, and the other portion F having a lower deformation resistance than the portion E is extended. By repeating the operation one after another, the portion with low deformation resistance can be stretched one after another without causing local thinning or breakage of the metal plate material to be molded. In other words, even with this method, it is possible to perform draw molding by hot pressing and form molding with severe curvature.

(N) Then, a means for forcibly lowering the temperature of the portion A where the plate thickness decreases due to elongation to forcibly increase the deformation resistance of the portion A, or a temperature of the portion D that does not require elongation due to molding is forced. As a means for forcibly increasing the deformation resistance of the part D by lowering to the above, in consideration of productivity and controllability, a plurality of coolant discharge ports are formed on the molding surface of the mold as shown in FIGS. And it is desirable to discharge a refrigerant | coolant from the formed refrigerant | coolant discharge port to the metal plate material which is a molding material.

(O) The position of the portion A where the plate thickness decreases due to the elongation or the portion D where the elongation accompanying the molding is unnecessary varies depending on the progress of the press molding, for example, the amount of punch pressing, but communicates with the refrigerant discharge port. By controlling a predetermined valve mechanism provided in the refrigerant supply pipe, the refrigerant can be discharged also to the part A or the part D whose position changes as the press molding progresses. Further, as described above, since the position of the part A or the part D changes according to the punch push-in amount, it is desirable to control the valve mechanism, that is, the refrigerant discharge timing in synchronization with the punch push-in amount. . Therefore, a mold having a plurality of refrigerant discharge ports on the molding surface of the above-described mold, a pipe communicating with the refrigerant discharge port inside the mold, and a refrigerant supply pipe having a predetermined valve mechanism is arranged in the mold. It is desirable to connect a predetermined control device that controls a predetermined valve mechanism included in the mold to control refrigerant discharge from each refrigerant discharge port.
2 and 3 are schematic explanatory views schematically showing the principle of the present invention, in which the refrigerant is discharged from the refrigerant discharge port at the position indicated by the black circle, and the deformation resistance of the metal plate material in the refrigerant discharge portion is shown. It shows that it is forcibly raised.

  Based on the above findings, the present inventor has developed heat that enables draw molding and form molding with severe curvature, which could not be realized by the conventional hot press molding technology, while maintaining the high productivity characteristic of press molding. The present inventors have conceived a hot press molding die, a hot press molding apparatus, and a hot press molding method. The gist is as follows.

(1) A hot press-molding mold comprising an upper mold and a lower mold for press-molding a heated metal plate material, comprising a plurality of coolant discharge ports and a lubricating liquid supply port on the molding surface of the mold, A pipe that communicates with each refrigerant discharge port and includes a first valve mechanism, and a lubricating liquid supply pipe that communicates with each lubricating liquid supply port and includes a second valve mechanism are arranged inside the mold. A hot press molding die characterized by the above.

(2) The hot press molding die according to (1) above, wherein a spray nozzle is provided in the lubricating liquid supply port.

(3) The hot press molding die as described in (1) or (2) above, wherein heating means for accelerating fixation of the solid lubricant to the molding surface is provided inside the die.

(4) Any one of the above (1) to (3), wherein a plurality of refrigerant recovery ports are provided on the molding surface of the mold, and a refrigerant recovery pipe communicating with each refrigerant recovery port is arranged inside the mold. 2. Hot press molding die according to item 1.

(5) A hot press forming apparatus for forming a heated metal plate material using a hot press forming die composed of an upper die and a lower die, and any one of (1) to (4) above The first press device for controlling the refrigerant discharge from each refrigerant discharge port by controlling the first valve mechanism provided in the hot press molding die, A hot press molding apparatus comprising: a second control device that controls a second valve mechanism provided in a hot press molding die to control supply of a lubricating liquid to each lubricating liquid supply pipe.

(6) A hot press forming method in which a heated metal plate material is formed using a hot press forming die composed of an upper die and a lower die, and the heated metal plate material is interposed between the upper die and the lower die. It is set and positioned, and a lubricant is discharged to a portion of a highly processed metal plate material, and after solid lubricant contained in the lubricant is fixed, press forming including stretching is started. A hot press molding method.

(7) The hot press molding as described in (6) above, wherein the solid lubricant is any one or a mixture of graphite, molybdenum disulfide, titania, tungsten sulfide, and mica. Method.

(8) During press molding from the start of molding to the completion of molding, a lubricating liquid in which the solid lubricant and the binder are dispersed or dissolved in one or more liquids of water, alcohol, and oil. Sliding between the hot press molding die and the metal plate material whose position changes according to the progress of the press molding from the lubricating liquid supply port or the lubricating liquid supply spray nozzle formed on the molding surface of the hot press molding die The hot press molding method according to (6) or (7), characterized in that the hot press molding method is supplied to a part.

(9) During press molding from the start of molding to the completion of molding, the refrigerant is discharged to at least a part of the metal plate material from the refrigerant discharge port formed on the molding surface of the hot press molding die. Increase the deformation resistance of the part, stretch the part with lower deformation resistance than that part, and repeat the above operation for the part where the plate thickness becomes thinner, thereby stretching other parts with lower deformation resistance one after another The hot press molding method according to any one of (6) to (8), wherein the molding process is performed.

(10) During press molding from the start of molding to the completion of molding, from the coolant discharge port formed on the molding surface of the hot press molding die, and the part where the plate thickness is reduced due to the elongation accompanying the molding of the metal plate material For either one or both of the parts that do not need to be stretched, the deformation resistance of the part is increased by discharging the refrigerant, and the part having a lower deformation resistance than the part is stretched. Any one of the above (6) to (8), wherein the thinning portion is subjected to molding by repeating the above-described operation, thereby drawing other portions having low deformation resistance one after another. Hot press molding method.

(11) After the press molding, the coolant is discharged from a coolant discharge port formed on the molding surface of the hot press molding die to a predetermined portion of the press-molded metal plate material to rapidly cool the predetermined portion. The hot press molding method according to any one of the above (6) to (10), wherein the strength of the predetermined part is increased.

(A) According to the hot press molding die according to the present invention, while maintaining high productivity that is a feature of press molding, draw molding by hot press and form molding with severe curvature, which was not possible with the prior art. It can be performed. Specifically, when deep drawing or the like is performed using conventional technology, even if local metal thinning or breakage occurs or can be prevented in the metal plate material to be molded, it is extremely productive. However, in the hot press molding die according to the present invention, the deformation resistance of each part of the molding material is pressed by the refrigerant discharge to the metal plate material from the plurality of refrigerant discharge ports formed on the molding surface. It can be controlled during molding, and the frictional resistance at the sliding part between the mold and the metal plate is controlled during press molding by supplying lubricating liquid from a plurality of lubricating liquid supply ports formed on the molding surface. As a result, it is possible to avoid deformation concentration and frictional heat generation at sliding parts that have a particularly high degree of processing, thereby preventing local thinning, breakage, and scratching of the metal plate, while increasing productivity. Hindrance One after another variant that can go extending the lower portion of the resistor, it is possible to freely control the elongation and thickness of the molded material each part without. At this time, since there is a lubricating liquid supply system separately from the refrigerant supply system, an appropriate amount of lubricant (lubricating liquid) is accurately supplied to necessary portions. The sprayed lubricant (lubricant) uses a solid lubricant, which is fixed by the heat of the metal plate or mold and is not washed away by the refrigerant when necessary. Further, since spraying is performed immediately before processing, there is an effect that unevenness of surface oxidation of the metal plate is not caused.

(B) Further, according to the hot press molding die according to the present invention, the cooling rate of each part of the metal plate material can be freely changed by the refrigerant discharge from the plurality of refrigerant discharge ports formed on the molding surface. Since it can do, the intensity | strength of each part of a press molded product can be arbitrarily set according to the objective. Specifically, for a portion requiring strength, the strength can be increased by martensitic transformation or bainite transformation by increasing the cooling rate by increasing the refrigerant discharge rate, the discharge flow rate, or the like. On the other hand, quenching hardness can be reduced by reducing the cooling rate for parts that require post-processing such as drilling (piercing) or cutting (trim), that is, parts that do not require strength. Moreover, if the cooling rate of the metal plate material during molding or after molding is different for each part of the molded product, press molded products having different strengths for each part of the molded product can be obtained.

(C) Furthermore, the hot press molding die according to the present invention can secure a sufficient cooling rate by the refrigerant discharge from the plurality of refrigerant discharge ports formed on the molding surface. Productivity can be improved by shortening the holding time.

(D) Moreover, the hot press molding apparatus which concerns on this invention controls the valve mechanism of the refrigerant | coolant supply pipe with which the said hot press molding die is equipped, and controls the refrigerant | coolant discharge from each refrigerant | coolant discharge port. Since it has a control device, it is possible to discharge refrigerant to the part where the plate thickness decreases due to the elongation that changes every moment according to the progress of press molding, or to the part that does not require elongation due to molding, Without causing local thinning or breakage of the metal plate as the molding material, the portions having low deformation resistance can be extended one after another.

(E) Similarly, the hot press molding apparatus according to the present invention controls the valve mechanism of the lubricating liquid supply pipe provided in the hot press molding die to supply the lubricating liquid to each lubricating liquid supply pipe. Since it has the 2nd control device which controls supply of the lubricating fluid from each lubricating fluid supply port to the sliding part of a metallic mold and a metal plate material, the metallic mold and metal plate which change every moment according to the progress of press molding It is possible to supply the lubricating liquid to the sliding part of the metal plate, thereby avoiding deformation concentration and frictional heat generation in the sliding part having a high degree of processing, and without affecting the productivity. It is possible to prevent local thinning, breakage, and flaws, and to further improve the draw moldability.

(F) Moreover, since the hot press molding method according to the present invention starts the press molding including the drawing process after fixing the solid lubricant to the part of the metal plate material having a high degree of processing in advance, the lubrication of the solid lubricant is performed. Due to the effect, it is possible to avoid deformation concentration, frictional heat generation and scratches in sliding parts with a high degree of processing, thereby making it possible to perform draw forming and curvature by hot pressing, which was not possible with conventional technology without impairing productivity. Strict foam molding can be performed.

Hereinafter, the best mode for carrying out the present invention will be described with reference to FIGS.
First, a heating method and a heating temperature of the molding material used in the present invention and the molding material before being set in the hot press molding die 2 will be described.
The molding material used in the present invention is a metal plate 1 and can be applied to any steel plate such as an Al-plated steel plate, a Zn-plated steel plate, a high-strength steel plate, and ordinary steel.
Further, a steel sheet that undergoes martensitic transformation or bainite transformation can be increased in strength by quenching by refrigerant discharge, and therefore, a steel plate that undergoes martensitic transformation or bainite transformation is desirable. It is not always necessary to transform the refrigerant when it is discharged, and it may be transformed after molding.
The method of heating the metal plate 1 is not particularly limited, and any method that can heat the metal plate 1 to the A1 transformation point or higher, heating in an electric furnace, gas furnace, flame heating, current heating, high frequency Any method such as heating or induction heating may be used.
In addition, about the site | part which needs post-processes, such as a piercing and a trim, you may mask in a heating furnace etc. previously, and you may lower the cooling start temperature. Alternatively, at the stage of transporting the heated metal plate 1 from the heating device such as a heating furnace to the hot press molding die 2, the cooling start temperature may be lowered by contact heat removal with the transport device.

  As shown in FIG. 4A, a hot press molding die 2 according to the present invention includes an upper die having a die 3, a pad 5, a die holder 9, and a die base 7, a punch 4, a plate presser 6, It is comprised from the lower mold | type provided with the punch holder 10 and the die base 8. FIG. The die holder 9 also serves as a pad holder, and the punch holder 10 serves as a plate holding holder. Hereinafter, these sets are referred to as a die set 11. FIG. 4B is a diagram in which the die holder 9 and the punch holder 10 are omitted in order to clarify the configuration of the hot press molding die 2 according to the present invention.

FIG. 5 is a cross-sectional view for explaining a hot press molding die 2 having a refrigerant discharge function and a lubricating liquid supply function according to the present invention.
FIG. 5 is a cross-sectional view in the case where the punch 4 has a refrigerant discharge function and the die 3 and the plate retainer 6 have a lubricating liquid supply function, but these functions are the die 3, the pad 5, the punch 4 and the plate. Desirably, at least one of the pressers 6 is provided. Hereinafter, the case where the punch 4 is provided with the refrigerant discharge function and the die 3 and the plate holder 6 are provided with the lubricating liquid supply function will be described.

As shown in FIG. 5, a hot press molding die 2 according to the present invention includes a plurality of refrigerant discharge ports 12 for discharging a refrigerant to a metal plate material 1 as a molding material, a die 2, and a metal plate material 1. A plurality of lubricating liquid supply ports 30 for supplying the lubricating liquid to the sliding portion are formed on the molding surface of the mold.
Further, inside the mold, a pipe communicating with each refrigerant discharge port 12 and having a first valve mechanism, and a pipe communicating with each lubricating liquid supply port 30 and a second valve mechanism 32. A lubricating liquid supply pipe 31 is provided.
5 shows an example in which the coolant discharge port 12 is formed in the vertical wall portion of the punch 4, but it may be formed in the top portion of the punch 4, or may be formed in both the vertical wall portion and the top portion. The same applies to the case where the refrigerant outlet 12 is formed in the plate presser 6. On the other hand, when the coolant discharge port 12 is formed in the upper die 3 or the pad 5, it may be formed at the bottom or at both the vertical wall and the bottom.
Similarly, FIG. 5 shows an example in which the lubricating liquid supply port 30 is formed in the vertical wall and bottom of the die 3 and the top of the plate presser 6, but the vertical wall and top of the punch 4 or the bottom of the pad 5. The lubricating liquid supply port 30 may be formed.

As the refrigerant used in the present invention, that is, the refrigerant discharged from the refrigerant discharge port 12 to the metal plate 1, water, polyhydric alcohols, polyhydric alcohol aqueous solution, polyglycol, Mineral oil with a flash point of 120 ° C or higher, synthetic ester, silicone oil, fluorine oil, grease with a drop point of 120 ° C or higher, mineral oil, or water emulsion in which a surfactant is blended with a synthetic ester may be used. May be.
The refrigerant may be liquid or gas. When a gas is used as the refrigerant, the heat transfer coefficient is low, so that it is limited to a case where the processing is not relatively severe, or a case where the martensite transformation or the bainite transformation is not performed. Also, it is desirable to use nitrogen, CO ₂ , or inert gas with low activity in order to avoid surface oxidation. Furthermore, when the refrigerant is a gas, it does not remain attached to the molded product or the hot press molding die 2, so that there is an effect that unnecessary dirt and rust are less likely to occur.

Next, the solid lubricant 36 used in the present invention will be described. As the solid lubricant 36, any one or a mixture of graphite, molybdenum disulfide, titania, tungsten sulfide, and mica can be used. When such a solid lubricant 36 is fixed in advance to a portion of the metal plate 1 having a high degree of processing and then hot press forming including drawing processing such as draw molding or form molding with severe curvature is started, the solid lubricant 36 Lubrication effect, that is, deformation concentration and frictional heat generation at a high degree of workability can be avoided, thereby preventing local metal thinning, breakage, and scratching of the metal plate 1, and draw formability Can be improved.
The timing for fixing the solid lubricant 36 to the metal plate 1 is to fix the solid lubricant 36 immediately before starting the press molding, for example, immediately after setting the heated metal plate 1 between the upper die and the lower die. Is desirable. At the stage where the metal plate 1 is set between the hot press forming molds 2 and positioned, the heated metal plate 1 is still in a high temperature state, so that it is extremely easy to perform without any special treatment. The solid lubricant 36 can be fixed to the metal plate 1. In other words, the solid lubricant 36 exerts its lubricating effect only after being fixed to the molding surface of the mold 2. In the method in which the operator applies the solid lubricant to the mold and fixes it every time press molding is performed. The working time is increased and the productivity is greatly reduced. Further, in order to shorten the working time, even if the solid lubricant 36 is applied to the metal plate 1 in advance, and this is heated and fixed, the solid lubricant and the binder are decomposed, and the solid lubricant Cannot perform the function. Alternatively, in the method of mixing the solid lubricant with the refrigerant, the solid lubricant is washed away by the refrigerant and cannot function as a solid lubricant. However, at the stage where the metal plate 1 is set between the molds 2 and positioned, the heated metal plate 1 is still in a high temperature state. At this time, solid lubrication is applied to the portion of the metal plate having a high degree of processing. When the lubricant in which the agent is dispersed or dissolved is discharged, the solid lubricant 36 contained in the lubricant can be fixed to the metal plate 1 very easily. Therefore, the heated metal plate 1 is set between the upper die and the lower die for positioning, and then solid lubrication is performed on a portion of the metal plate having a high degree of processing, that is, a portion where the sliding between the metal plate and the mold is severe. When the hot press molding including the drawing process is started after the lubricant liquid in which the agent 36 is dispersed or dissolved is discharged and the solid lubricant contained in the lubricant liquid is fixed, the solid is not disturbed. Lubricating effect by the lubricant, that is, deformation concentration and frictional heat generation in a portion with a high degree of processing can be avoided, thereby preventing local metal thinning, breakage, and scratching of the metal plate material.
As for the method of fixing the solid lubricant 36 to the metal plate 1, as described above, the lubrication liquid in which the solid lubricant 36 and the binder are dispersed or dissolved in a predetermined liquid is formed on the molding surface of the mold 2. It is desirable to apply from the liquid supply port 30 or the spray nozzle for supplying the lubricating liquid. By discharging or spraying the lubricating liquid, the solid lubricant 36 can be uniformly fixed on the surface of the metal plate 1. Further, since the lubricating liquid supply port 30 or the lubricating liquid supply spray nozzle passes through the lubricating liquid supply pipe 31 and the second valve mechanism 32, an appropriate amount can be supplied to an appropriate portion. Further, since the supply is performed immediately before the press working, it is possible to prevent the metal plate material 1 from causing uneven oxidation. In addition, since the solid lubricant 36 is immediately fixed to the metal plate 1, there is an effect that the solid lubricant 36 does not have to be washed away by the refrigerant until necessary.

Next, the lubricating liquid used in the present invention will be described in detail. The lubricating liquid is obtained by dispersing or dissolving a powdered solid lubricant 36 and a binder in a predetermined liquid as described above.
As the liquid, any one or more of water, alcohol and oil can be used. By dispersing or dissolving the solid lubricant 36 in such a liquid, the solid lubricant 36 can easily flow into the sliding portion between the mold 2 and the metal plate 1. In the lubricating liquid that has reached the sliding portion that requires lubrication, the liquid component is evaporated by the heat of the metal plate material, and the solid lubricant 36 remains fixed. A lubrication effect is exerted by the solid lubricant 36 thus fixed.
The binder is not particularly limited as long as it is water-soluble, and for example, PVA (polyvinyl alcohol) can be used. By dispersing or dissolving the binder, the solid lubricant 36 is easily fixed to the molding surface of the mold 2 or the surface of the metal plate 1 and the draw moldability is improved.
The liquid preferably contains a resin as necessary. By containing the resin, the solid lubricant 36 is easily fixed to the molding surface of the mold 2 or the surface of the metal plate 1 and the draw moldability is improved.

The coolant discharge port 12 and the coolant supply pipe 13 communicating therewith, and the lubricant supply port 30 and the lubricant supply tube 31 communicating therewith can be formed by mechanical drilling by drilling or drilling by electric discharge machining. In this case, as a material of the mold 2, it is desirable to use hot working die steel from the viewpoint of hot strength.
In addition, since the refrigerant supply pipe 13 fulfills the refrigerant discharge function as long as it communicates with the refrigerant discharge port 12, it penetrates from the inside of the mold to the outer surface instead of drilling the refrigerant discharge port 12 and the refrigerant supply pipe 13 in the mold. The refrigerant supply pipe 13 may be connected to a porous metal having pores. In this case, it is desirable to use a porous metal having a plurality of holes having a diameter of 100 μm to 1 mm and a pitch of 100 μm to 10 mm penetrating in the thickness direction. For example, in the punch 4 having the configuration shown in FIG. 6, if the core 20 is made of die steel and the punch 4 is made of a porous metal, the coolant discharge port 12 and the coolant supply pipe 13 having a small pitch can be formed. . Such a porous metal can be produced by unidirectional solidification in which the direction of the solidified structure is made constant by temperature control after sintering the powder after molding or by melting the metal. At this time, the lubricating liquid supply pipe 31 is separately provided so as not to be mixed with the refrigerant.
Further, as shown in FIGS. 9 and 10, a lubricant supply spray nozzle may be provided in the opening of the lubricant supply port 30. In that case, it is necessary to connect the lubricating liquid supply spray nozzle and the lubricating liquid supply pipe 31 so as to communicate with each other. By providing a spray nozzle for supplying a lubricating liquid on the molding surface of the mold, the metal plate material before the start of press molding, particularly the degree of processing, on the sliding portion between the mold 2 and the metal plate material 1 as described above. The lubricating liquid can be uniformly distributed to the portion of the metal plate material having a high height. As a result, local metal thinning, breakage, and scratching of the metal plate 1 can be prevented, and the draw formability can be improved. In the following description, the lubricating liquid supply port provided with the lubricating liquid supply spray nozzle is also referred to as the lubricating liquid supply port 30 unless otherwise specified.

Further, as shown in FIGS. 7 to 10, if a plurality of protrusions 19 are formed on the molding surface of the hot press molding die 2, the contact area between the die 2 and the metal plate 1 is reduced, and the press It is possible to suppress overcooling of the metal plate 1 which is a material to be molded due to heat removal from the mold during molding. Conversely, by increasing the contact area between the material to be molded and the refrigerant, a large amount of refrigerant can be brought into contact with the portion to be rapidly cooled, and the cooling rate can be increased as required. Furthermore, when the coolant is discharged at the bottom dead center after the molding is completed, it becomes easy to circulate the coolant in the gap between the projection 19 and the metal plate 1, and the mold 2 and the metal plate 1 are cooled. Efficiency can be increased. Moreover, not only this but the thermal distortion of the metal mold | die 2 can be reduced and a processing precision can be raised.
Further, by forming a plurality of protrusions 19 on the molding surface of the mold 2, the solid lubricant 36 contained in the lubricating liquid supplied to the sliding portion between the mold 2 and the metal plate material 1 is converted into the mold 2. It becomes easy to adhere to the molding surface, and the draw moldability is improved.
7 to 10 have a cylindrical shape provided on the molding surface of the mold 2 at a predetermined interval, but the horizontal cross section has a circular shape, a polygonal shape, or a star shape. Desirably, the shape of the vertical cross section is preferably rectangular or trapezoidal, and may be hemispherical.

The protrusion 19 can exert the above-described effect if it is formed on at least one of the molding surfaces of the mold 2, but may be formed on both molding surfaces. Further, it may be provided on a part of the molding surface of the mold 2 or on the entire surface.
In addition, since the shape of the protrusion 19 may be transferred to the press-molded product and harm the surface property of the molded product, the mold portion around the protrusion is removed to form a recess, or as shown in FIG. Thus, it is desirable to form a recess having a depth matching the height of the protrusion in the mold portion at the protrusion formation position, and to form the protrusion 19 in the recess.

The area ratio of the protrusions 19 is desirably 1 to 90% of the molding surface of the mold 2. If it is less than 1%, the shape of the protrusion 19 is easily transferred to the material to be molded, and if it exceeds 90%, the gap between the protrusions 19 is narrow, the pressure loss increases, and the refrigerant cannot be charged or flown. . Further, since the supplied lubricating liquid cannot be filled or flowed, it becomes difficult to fix the solid lubricant 36 to the sliding portion between the mold 2 and the metal plate 1.
When the horizontal cross-sectional shape of the protrusion 19 is circular, the diameter of the protrusion 19 is preferable. When the protrusion 19 has a polygonal shape or a star shape, the diameter of the circumscribed circle of the protrusion is preferably 10 μm to 5 mm. When the diameter of the protrusion or the circumscribed circle is less than 10 μm, the wear of the protrusion is great, and the effect cannot be exhibited over a long period of time, and when it exceeds 5 mm, cooling cannot be performed uniformly.
As for the height of the projection part 19, it is desirable that they are 5 micrometers-1 mm. If the height of the protrusion is less than 5 μm, the gap with the material to be molded is too small, so it is difficult to circulate the coolant or lubricant between the mold 2 and the metal plate 1. It becomes excessive and the cooling rate due to the heat conduction of the refrigerant decreases.

The protrusion 19 can be formed by electrolytic processing, chemical etching, electric discharge processing, plating, or the like.
In chemical etching, a visible light curable photosensitive resin is applied to the mold surface, dried, then covered with a mask that blocks visible light, irradiated with visible light, the irradiated part is cured, and a resin other than the cured part is applied. This is a method of removing with an organic solvent. For example, the mold surface may be immersed in an etching solution such as a sodium chloride aqueous solution for about 1 to 30 minutes and etched. The diameter or pitch of the protrusions can be appropriately selected depending on the shape of the mask that blocks visible light, and the height of the protrusions can be appropriately adjusted depending on the etching time.
Electric discharge machining is a machining method in which a copper electrode having a concave portion in which a target protrusion shape is inverted as a surface pattern is placed facing a mold, a current peak value and a pulse width are changed, and a DC pulse current is passed. . A preferable current value is 2 to 100 A, a pulse width is 2 to 1000 μsec, and the current value may be appropriately adjusted according to the mold material and the desired protrusion shape.
In the case of the plating method, in order to make the diameter of the hemispherical protrusion 10 μm or more, the thickness of the plating is preferably 10 μm or more, and the upper limit is preferably 80 μm or less in order to prevent peeling. The plating layer can be formed at a predetermined bath temperature and current density after alkaline degreasing and electrolytic etching in which a mold is used as an anode in a plating solution. In the case of chromium plating, the current density is about 1 to 200 A / dm ^{2 in the} chromium plating solution, and the bath temperature is about 30 to 60 ° C. In the case of NiW plating, the current density is 1 to 100 A / dm ^{2 in the} NiW plating solution. When the bath temperature is about 30 to 80 ° C., a plating layer having a thickness of 10 to 80 μm can be provided. In order to form a plating layer having a hemispherical convex shape, for example, after increasing the current density stepwise, plating may be performed at a constant current density.

Furthermore, as shown in FIG. 10, by providing one or more heating means 35 inside the hot press molding die 2, the solid lubricant 36 can be firmly fixed to the molding surface. For example, FIGS. 9 and 10 are schematic views when the solid lubricant 36 is fixed only to the left half of the molding surface by heating by the left half heating means 35 provided inside the mold. By controlling the heating means 35 provided inside the mold, the solid lubricant 36 can be fixed only in a necessary range.
As the heating means 35, there are energization heating, infrared heat beam, laser beam, induction heating, etc., but an electric heater is desirable.

As shown in FIGS. 7 and 8, a plurality of refrigerant recovery ports 17 are formed on the molding surface of the hot press molding die 2, and a refrigerant recovery pipe 18 communicating with the refrigerant recovery ports 17 is disposed inside. The refrigerant discharged to the metal plate 1 can be recovered efficiently. Furthermore, the cooling efficiency can be improved by recovering the refrigerant from the refrigerant recovery pipe 18 by suction means such as a vacuum generator. This is because the refrigerant that has not been vaporized adheres or accumulates along the molding surface of the mold 2, for example, adheres to or accumulates on the bottom of the protrusion 19, but contributes to cooling in the adhering part or the like. This is because, when the refrigerant is newly discharged, the heat transfer coefficient α at the adhering portion or the like is lower than when the refrigerant does not remain. For this reason, after the refrigerant is discharged, it is desirable to collect the refrigerant that has not been vaporized by a suction means such as a vacuum generator, thereby improving the control of the cooling efficiency and the heat transfer coefficient α. Furthermore, it is possible to efficiently recover the solid lubricant 36 that has not been fixed or has been separated from the lubricant.
The refrigerant recovery port 17 and the refrigerant recovery tube 18 can be formed by the same method as the refrigerant discharge port 12 and the refrigerant supply tube 13 described above. Moreover, the refrigerant | coolant collection | recovery port 17 may be provided in the top part of the punch 4, and may be provided in both a vertical wall part and a top part. The same applies to the case where the refrigerant recovery port 17 is provided in the plate holder 6. On the other hand, when the coolant recovery port 17 is provided in the upper die 3 or the pad 5, it may be provided at the bottom or at both the vertical wall and the bottom, but is provided at the vertical wall. Thus, the refrigerant discharged to the molding material can be efficiently recovered.

Next, functions of the first valve mechanism provided in the refrigerant supply pipe 13, that is, the on-off valve 14, the flow rate adjustment valve 15, and the pressure adjustment valve 16 will be described.
In general, the cooling capacity by the refrigerant can be expressed using a heat transfer coefficient α, and the relationship between the heat transfer coefficient α, the refrigerant discharge amount Q, the discharge flow rate U, the discharge pressure P, and the discharge time T is expressed by the following equation. Can be represented. Note that f, g, and h represent functions, for example, that the heat transfer coefficient α is established as a function of the refrigerant discharge amount Q.
Heat transfer coefficient α = f (refrigerant discharge amount Q) (1)
Refrigerant discharge amount Q = g (discharge flow velocity U, discharge time T) (2)
Discharge flow rate U = h (discharge pressure P) (3)

That is, according to the present invention, the refrigerant discharge amount Q, the discharge flow rate U, the discharge pressure P, the discharge time T, the at least one of the on-off valve 14, the flow rate adjustment valve 15, and the pressure adjustment valve 16 provided in the refrigerant supply pipe 13. And one or two or more parameters selected from the discharge timing, thereby controlling the heat transfer coefficient. That is, in the present invention, it is not always necessary to provide three types of valves, that is, the on-off valve 14, the flow rate adjusting valve 15, and the pressure adjusting valve 16, and the function can be achieved by one valve. However, by providing three types of valves, that is, the on-off valve 14, the flow rate adjusting valve 15, and the pressure adjusting valve 16, the parameters can be easily controlled. It is desirable to provide a type of valve.
The valve may be built in the mold close to the refrigerant discharge port 12 in order to keep the responsiveness good. However, it takes time to disassemble the mold every time the valve is adjusted. It is desirable to install in.

Further, as described above, the present invention controls one or more parameters selected from the refrigerant discharge amount Q, the discharge flow rate U, the discharge pressure P, the discharge time T, and the discharge timing by at least one valve. Thus, the heat transfer coefficient α by the refrigerant discharge is controlled. If this control is performed for each refrigerant discharge port, cooling by the refrigerant discharge from the plurality of refrigerant discharge ports 12 formed on the molding surface of the mold 2 is performed. The heat transfer coefficient α of the metal plate 1 can be freely changed, and the strength of each part of the material to be molded can be arbitrarily controlled. Thus, it is possible to freely control the elongation and thickness of each part of the metal plate.
Furthermore, when forming a columnar press product, the moldability can be improved by grouping and controlling the refrigerant discharge from a plurality of refrigerant discharge ports 12 in the positional relationship where the punch push-in amount is the same. It is possible to make it. In addition, control efficiency can be improved by grouping.

The second valve mechanism 32 provided in the lubricating liquid supply pipe 31 is not particularly limited, and a valve equivalent to the on-off valve 14 provided in the refrigerant supply pipe 13 can be used.
The valve may be built in the mold close to the lubricating liquid supply port 30 in order to keep the responsiveness good. However, since it takes time to disassemble the mold every time the valve is adjusted, 11 is desirable.

Next, the 1st control apparatus 23 which controls the refrigerant | coolant discharge from each refrigerant | coolant discharge port 12 by controlling the 1st valve mechanism with which the refrigerant | coolant supply pipe | tube 13 is provided is demonstrated. In addition, the said 1st control apparatus 23 is one of the elements which comprise the hot press molding apparatus 38 which concerns on this invention with the above-mentioned hot press molding die 2 as shown in FIG.
The first control device 23 is not particularly limited, and may be mechanical as long as it can control the opening / closing of the on / off valve 14, the flow rate adjusting valve 15 and the pressure adjusting valve 16 included in the refrigerant supply pipe 13. Any electronic means or a combination of these may be used. For example, by employing a relay switch for these valve mechanisms and controlling the opening and closing (on / off) of the relay switch by a computer (computer), the refrigerant discharge from the refrigerant discharge port 12 communicating with the refrigerant supply pipe 13 As a result, the heat transfer coefficient α at the refrigerant discharge port 12 can be adjusted.

Moreover, since it is desirable that the refrigerant discharge timing from the refrigerant discharge port 12 is synchronized with the punch pressing amount (also referred to as a stroke position), measurement data indicating the punch pressing amount or a signal (stroke signal 39) corresponding thereto is obtained. Input to the first control device 23 is desirable. Thereby, it is possible to control the on-off valve 14, the flow rate adjustment valve 15, and the pressure adjustment valve 16 provided in the refrigerant supply pipe 13 in synchronization with the punch push-in amount, and communicate with the refrigerant supply pipe 13. It becomes possible to synchronize the refrigerant discharge from the refrigerant discharge port 12 with the punch push-in amount.
In the case of forming a columnar press product, the formability is improved by making the refrigerant discharge at the plurality of refrigerant discharge ports 12 in the positional relationship where the punch push-in amount is the same, in this case, It is desirable to make the control of the on-off valve and the like of the refrigerant supply pipe 13 communicating with the plurality of refrigerant discharge ports 12 in the positional relationship where the punch push-in amount is the same.

The second control device 37 that controls the second valve mechanism 32 provided in the lubricating liquid supply pipe 31 to control the supply of the lubricating liquid to the lubricating liquid supply pipe 31 is not particularly limited. As long as the opening and closing of the valve mechanism 32 can be controlled, any mechanical or electronic means or a combination of these may be used. In addition, the said 2nd control apparatus 37 is also one of the elements which comprise the hot press molding apparatus 38 which concerns on this invention with the above-mentioned hot press molding die 2 as shown in FIG.
Further, since it is desirable to synchronize the supply timing of the lubricating liquid to the lubricating liquid supply pipe 31 and the supply timing of the lubricating liquid from the lubricating liquid supply port 30 with the punch push-in amount (also referred to as the stroke position), as shown in FIG. It is desirable to input the stroke signal 39 to the second control device 37. Thus, the second valve mechanism 32 can be controlled in synchronization with the punch push-in amount, and the supply of the lubricant from the lubricant supply port 30 can be synchronized with the punch push-in amount.
Further, in the case of forming a columnar press product, the formability is improved by making the lubricating liquid supply in the plurality of lubricating liquid supply ports 30 in the same positional relationship that the punch push-in amount is the same, in this case For this, it is desirable that the control of the second valve mechanism 32 provided in the lubricating liquid supply pipe 31 communicating with the plurality of lubricating liquid supply ports 30 in the positional relationship where the punch push-in amount is the same is the same.

That is, as shown in FIG. 11, the hot press molding apparatus 38 according to the present invention includes a hot press molding die 2 having a refrigerant discharge function and a lubricating liquid supply function, and a first die provided in the die 2. Lubrication to the lubricating liquid supply pipe 31 by controlling the first control device 23 that controls the valve mechanism to control the refrigerant discharge from each refrigerant discharge port 12 and the second valve mechanism 32 provided in the mold 2. It has the 2nd control apparatus 37 which controls supply of a liquid.
For this reason, the lubrication effect by the solid lubricant 36 effective for improving the draw moldability disappears due to the consumption of the solid lubricant, so that the hot press molding apparatus 38 according to the present invention having the second control device 37 is used. Accordingly, even during the press molding from the start of molding to the completion of molding, the hot press molding die 2 and the hot press molding die 2 are formed from the lubricating liquid supply port 30 formed on the molding surface of the hot press molding die 2. The lubricating liquid can be supplied to the sliding portion with the metal plate 1 without hindering productivity.
In addition, the position of the sliding portion between the hot press-molding die 2 and the metal plate 1, particularly the sliding portion having a high degree of processing, changes according to the progress of press molding, for example, the amount of punch press-in. According to the hot press molding apparatus 38 according to the present invention having the apparatus 37, even if the press molding from the start of molding to the completion of molding is being performed, the sliding portion whose position changes according to the progress of press molding. The lubricating liquid can be supplied without impeding productivity.
As described above, the heated metal plate 1 is set between the upper die and the lower die for positioning, and then the portion of the metal plate having a high degree of processing, that is, the sliding between the metal plate 1 and the mold 2 is performed. When the lubricating liquid in which the solid lubricant 36 is dispersed or dissolved is discharged to a severe part and the solid lubricant contained in the lubricating liquid is fixed, and hot press molding including stretching is started, productivity is increased. Without obstructing, it is possible to avoid the lubrication effect by solid lubricant, that is, deformation concentration and frictional heat generation in a highly processed part, thereby preventing local thinning, breakage and scratching of the metal plate material. It is possible to improve the draw moldability, and it goes without saying that the solid lubricant fixing process before the start of the press molding can be realized using the second control device 37.
That is, according to the hot press molding apparatus 38 according to the present invention having the second control device 37, the solid lubricant can be used even before the press molding is started or during the press molding from the molding start to the molding completion. Since the lubrication effect of No. 36 can always be exhibited, while maintaining the high productivity that is the feature of press molding, draw forming by hot pressing and severe curvature foam that could not be realized by conventional hot press forming technology Molding can be performed.

Further, as described above, the position of the portion where the plate thickness decreases due to the elongation accompanying press forming can be specified by an experiment performed in advance, and the hot press forming apparatus according to the present invention having the first control device 23 is provided. As shown in FIG. 2, the temperature of the portion A where the plate thickness decreases as a result of elongation can be forcibly lowered by the refrigerant discharge from the refrigerant discharge port 12, and the deformation resistance of the portion A can be forced. Can be raised. And the other part B whose deformation resistance is relatively lower than the said part A can be extended | stretched. Further, the temperature of the portion B can be forcibly lowered by the refrigerant discharge from the refrigerant discharge port 12 with respect to the portion B where the plate thickness is reduced due to the elongation, and the deformation resistance of the portion B is reduced. Can be forcibly raised. And the other part C whose deformation resistance is relatively lower than the said part B can be extended | stretched.
That is, according to the hot press molding apparatus 38 according to the present invention having the first control device 23, the hot press molding die 2 can be used even during press molding from the start of molding to the completion of molding. By discharging the refrigerant from a plurality of refrigerant discharge ports 12 formed on the molding surface to at least a part of the metal plate 1, for example, a part where the plate thickness becomes thin due to elongation accompanying molding, the deformation resistance of the part is increased. Since the parts with low deformation resistance can be stretched one after another, while maintaining the high productivity that is the feature of press molding, the form with severe draw and curvature that could not be realized by the conventional hot press molding technology Molding can be performed.

Further, according to the hot press molding apparatus 38 according to the present invention having the first control device 23, as shown in FIG. 3, even when the press molding is in progress from the start of molding to the completion of molding, The deformation resistance of the portion D that is not desired to be stretched by the refrigerant discharge from the refrigerant discharge port 12 formed on the molding surface 2 is forcibly increased in advance, and other deformation resistance relatively lower than that portion D is obtained. The part E is stretched, and for this reason, the part E in which the plate thickness is reduced due to elongation is newly forcedly increased by the refrigerant discharge and the deformation resistance is relatively lower than the part E. Since the operation of stretching the portion F of the metal plate 1 can be performed, the portion having a low deformation resistance one after another without causing local thinning and breakage of the metal plate 1 as the molding material by repeating the operation. Stretching process It can be.
That is, according to the hot press molding apparatus 38 according to the present invention having the first control device 23, it was not possible to achieve with the conventional hot press molding technology while maintaining high productivity that is a feature of press molding. Draw molding by hot pressing and foam molding with severe curvature can be performed.

Furthermore, according to the hot press molding apparatus 38 according to the present invention having the first control device 23, the metal is discharged by the refrigerant discharge from the refrigerant discharge port 12 formed on the molding surface of the hot press molding die 2. Since the cooling rate of each part of the plate material can be freely changed, the strength of each part of the press-formed product can be arbitrarily set according to the purpose.
In particular, after the press molding, from the coolant discharge port 12 formed on the molding surface of the hot press molding die 2, the coolant is discharged to a predetermined part of the press-molded metal sheet 1 and rapidly cooled. The strength of the predetermined part can be increased. For example, when the predetermined part is a part requiring strength, the strength can be increased by martensitic transformation or bainite transformation by increasing the cooling rate. On the other hand, when the predetermined part is a part that requires post-processing such as drilling (piercing) or cutting (trim), the quenching hardness can be lowered by reducing the cooling rate.

  That is, according to the hot press molding apparatus 38 according to the present invention having the first control device 23 and the second control device 37, the conventional hot press is maintained while maintaining high productivity which is a feature of press molding. It is possible to perform draw molding by hot pressing and form molding with severe curvature, which could not be realized by molding technology, and arbitrarily set the strength of each part of the press-molded product according to the purpose.

It is a schematic diagram for demonstrating the cause of the fracture | rupture accompanying draw molding. It is a schematic diagram for demonstrating an example of the shaping | molding method using the metal mold | die which concerns on this invention. It is a schematic diagram for demonstrating another example of the shaping | molding method using the metal mold | die which concerns on this invention. It is a schematic explanatory drawing of the metal mold | die which concerns on this invention, (a) is the figure which described the die holder and the punch holder, (b) is the figure which abbreviate | omitted and described the die holder and the punch holder in order to clarify a structure. It is. It is sectional drawing for demonstrating the metal mold | die 2 provided with the refrigerant | coolant discharge function and lubricating liquid supply function which concern on this invention. It is explanatory drawing which shows the metal mold | die which concerns on this invention, and is sectional drawing at the time of providing the refrigerant | coolant discharge function in the punch. It is explanatory drawing which shows an example of the metal mold | die which concerns on this invention, and is a figure which shows the surface of the metal mold | die which formed the refrigerant | coolant discharge port, the refrigerant | coolant collection port, and the projection part. It is sectional drawing which shows an example of the metal mold | die which concerns on this invention, and is a figure which shows the cross section of the metal mold | die which formed the refrigerant | coolant discharge port, the refrigerant | coolant collection port, and the projection part. It is explanatory drawing which shows an example of the metal mold | die which concerns on this invention, and is a figure which shows the surface of the metal mold | die in which the lubricating liquid supply port, the lubricating liquid collection port, and the projection part were formed. It is explanatory drawing which shows an example of the metal mold | die which concerns on this invention, and is a figure which shows the metal mold | die which formed the lubricating liquid supply port, the lubricating liquid collection port, and the projection part in the molding surface, and was equipped with the heating means inside. It is sectional drawing which shows typically the hot press molding apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal plate material 2 Hot press molding die 3 Dies 4 Punch 5 Pad 6 Plate presser 7 Die base (upper die) 8 Die base (lower die)
DESCRIPTION OF SYMBOLS 9 Die holder 10 Punch holder 11 Die set 12 Refrigerant discharge port 13 Refrigerant supply pipe 14 On-off valve 15 Flow rate adjustment valve 16 Pressure adjustment valve 17 Refrigerant recovery port 18 Refrigerant recovery pipe 19 Protrusion part 20 Core 21 Seal 22 Mold whole cooling part 23 1st control apparatus 30 Lubricating liquid supply port (spray nozzle for lubricating liquid supply)
31 Lubricant supply pipe 32 Second valve mechanism 35 Heating means 36 Solid lubricant 37 Second control device 38 Hot press molding device 39 Stroke signal

Claims (11)

A hot press molding die comprising an upper mold and a lower mold for press-molding a heated metal plate material,
Equipped with a plurality of coolant discharge ports and lubricating liquid supply ports on the molding surface of the mold,
A refrigerant supply pipe which is a pipe communicating with each refrigerant discharge port inside the mold and includes a first valve mechanism;
A hot press molding die characterized in that a lubricating liquid supply pipe provided with a second valve mechanism is provided that communicates with each lubricating liquid supply port.
The hot press molding die according to claim 1, wherein a spray nozzle is provided in the lubricating liquid supply port.
3. The hot press molding die according to claim 1, further comprising a heating unit that promotes adhesion of the solid lubricant to the molding surface inside the die.
Equipped with multiple coolant recovery ports on the molding surface of the mold,
The hot press molding die according to any one of claims 1 to 3, wherein a refrigerant recovery pipe communicating with each refrigerant recovery port is arranged inside the die.
A hot press molding apparatus for molding a heated metal plate material using a hot press molding die composed of an upper mold and a lower mold,
A hot press molding die according to any one of claims 1 to 4,
A first control device that controls a first valve mechanism provided in the hot press molding die to control refrigerant discharge from each refrigerant discharge port;
A hot press molding apparatus comprising a second control device that controls a second valve mechanism provided in the hot press molding die to control supply of the lubricating liquid to each lubricating liquid supply pipe. .
A hot press molding method for molding a heated metal plate material using a hot press molding die composed of an upper mold and a lower mold,
Set the heated metal plate between the upper mold and the lower mold and perform positioning.
The lubricating liquid is discharged to the part of the metal plate material with a high degree of processing,
After fixing the solid lubricant contained in the lubricating liquid,
A hot press molding method characterized by starting press molding including stretching.
The hot press molding method according to claim 6, wherein the solid lubricant is any one of graphite, molybdenum disulfide, titania, tungsten sulfide, and mica, or a mixture of two or more thereof.
During press molding from the start of molding to the completion of molding,
A lubricating liquid in which the solid lubricant and the binder are dispersed or dissolved in one or more liquids of water, alcohol, and oil;
From the lubricating liquid supply port or the lubricating liquid supply spray nozzle formed on the molding surface of the hot press molding die,
The hot press molding method according to claim 6 or 7, wherein the hot press molding method is supplied to a sliding portion between a hot press molding die and a metal plate material whose position changes in accordance with the progress of press molding.
During press molding from the start of molding to the completion of molding,
From the refrigerant outlet formed on the molding surface of the hot press molding die,
For at least part of the metal plate,
By discharging the refrigerant, the deformation resistance of the part is increased, the part having a lower deformation resistance than the part is stretched, and the part where the plate thickness is reduced by repeating the above operation, the deformation resistance is successively increased. The hot press molding method according to any one of claims 6 to 8, wherein the other low part is stretched to perform molding.
During press molding from the start of molding to the completion of molding,
From the refrigerant outlet formed on the molding surface of the hot press molding die,
For either one or both of the part where the plate thickness is reduced by the elongation associated with the molding of the metal plate material and the part where the elongation associated with the molding is unnecessary,
By discharging the refrigerant, the deformation resistance of the part is increased, the part having a lower deformation resistance than the part is stretched, and the part where the plate thickness is reduced by repeating the above operation, the deformation resistance is successively increased. The hot press molding method according to any one of claims 6 to 8, wherein the other low part is stretched to perform molding.
After press molding,
From the refrigerant outlet formed on the molding surface of the hot press molding die,
For a given part of the press-molded metal plate,
By rapidly cooling the predetermined part by discharging the refrigerant,
The hot press molding method according to any one of claims 6 to 10, wherein the strength of the predetermined part is increased.

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