JP2017070973A - Hot pressing mold, and manufacturing method of hot pressing molding by using the hot pressing mold - Google Patents

Abstract

In a hot press machine having an upper die and a lower die, a configuration capable of manufacturing a hot press-formed product with higher dimensional accuracy with higher productivity is realized. An upper mold 11 has a plurality of refrigerant flow paths 12 formed therein, and a plurality of refrigerant ejection holes 11b which are outlets of the plurality of refrigerant flow paths 12 are formed on a contact surface with the steel plate 2. The formed upper mold body 15 and the opening / closing valves 31 provided in the plurality of refrigerant flow paths 12 in the upper mold body 15 are provided. [Selection] Figure 1

Description

  The present invention relates to a hot press die used for hot press molding.

  2. Description of the Related Art In recent years, hot press forming has been adopted as a steel plate forming means for automobile parts using high-tensile steel plates. In hot press forming, a steel sheet is press-formed at a high temperature and then quenched and hardened by quenching. Therefore, it is possible to obtain a high-strength and high-shape precision component without causing problems such as deformation after the press machine reaches the bottom dead center (hereinafter simply referred to as molding).

  In general, in hot press forming, a steel plate that has been heated to a predetermined temperature above the Ac3 transformation point in advance by a heating furnace or the like is placed on a die of a mold or lifted by a jig such as a lifter incorporated in the mold. In this state, the mold punch is lowered to the bottom dead center and then molded into a predetermined shape, and then rapidly cooled by a mold in which a cooling medium (refrigerant) flows in the clamped state. Quench. However, in such a configuration in which a steel plate molded product (molded product obtained by molding a steel plate with a mold) is cooled using a mold in which a refrigerant flows, the mold is again heated to a temperature at which hot press molding can be performed. Productivity is low because it takes time to cool the mold. Moreover, since the cooling capacity is insufficient when the thickness of the steel sheet to be hot-pressed is thick, the steel sheet molded product cannot be quenched.

  On the other hand, there is a method of rapidly cooling a steel sheet molded article by supplying a coolant such as water between the steel sheet molded article and the mold. The mold used in this method is provided with a plurality of independent protrusions having a certain height and a refrigerant ejection hole for the refrigerant on the surface. The mold is provided with a refrigerant flow path communicating with the refrigerant ejection hole and a flow path for sucking the refrigerant supplied to the mold.

  In the cooling method in which the mold having such a configuration is used for cooling the steel sheet molded product, the coolant is supplied to the flow path while cooling the steel sheet molded product through the flow path in the mold. The flow rate of the refrigerant is kept constant. Therefore, during the cooling period of the steel sheet molded product, the flow rate of the refrigerant ejected from each refrigerant ejection hole of the mold is the same.

  If a cooling method for cooling the steel sheet molded product by flowing a coolant between the steel sheet molded product and the mold as described above is employed, it is not necessary to secure a cooling time for the mold. Even if it is large, it can be quenched by increasing the refrigerant flow rate. However, when the flow rate of the refrigerant is increased, the shape and hardness of the hot press-formed product may vary depending on the part of the steel plate product. As a cause of such variation, it is conceivable that the cooling conditions are different due to the fact that the flow of the refrigerant is not the same between the vicinity of the coolant injection hole of the mold and the surrounding portion. In other words, because the cooling conditions of the steel sheet molded product are non-uniform, thermal stress is generated in the steel sheet molded product, and as a result, the quality including the dimensional accuracy and hardness after cooling of the hot press molded product varies. It is done.

  For example, Patent Document 1 discloses that cooling unevenness occurs in an annular shape around a coolant ejection hole of a mold. Further, in Patent Document 1, when cooling the steel sheet molded product, when cooling medium is ejected at a predetermined ejection amount from the beginning of cooling, bumping or air entrainment may cause the coolant ejection holes to be cooled. It is also disclosed that the cause is concentric circles at the center.

  In response to the above-described problem, Patent Document 1 discloses that after cooling is performed on a steel plate molded product by supplying a coolant to a coolant ejection hole of a mold, pre-cooling is performed while suppressing the ejection amount per unit time. A configuration is disclosed in which main cooling is performed by increasing the amount of refrigerant jetted from the refrigerant jet holes per unit time.

International Publication No. 2015/037657

  By the way, even when the steel sheet molded product is cooled by the cooling method disclosed in Patent Document 1, depending on the shape of the hot-pressed target part, the dimensional accuracy may be deteriorated. For example, when the shape of the hot-pressed target part is a deep dish shape that is greatly deformed in the thickness direction of the steel plate, the coolant is applied to the steel plate molded product in the part where the coolant flow path in the hot press mold is long. The arrival timing is later than other parts. Therefore, in the initial stage of cooling of the steel plate molded product, uneven cooling of the steel plate molded product occurs, and as a result, unexpected internal stress is generated in the steel plate molded product, which may cause deterioration of dimensional accuracy. .

  On the other hand, in the structure of patent document 1, the method of reducing a cooling nonuniformity by lengthening the period of pre-cooling can be considered. When extending the pre-cooling period, switch to main cooling after the refrigerant has reached the refrigerant injection hole in the part where the coolant flow path in the hot press mold is long and the cooling timing is slow compared to other parts. It is done. Therefore, the timing of the rapid cooling start by the refrigerant is the same timing in the hot press mold. Therefore, the deterioration of the dimensional accuracy of the hot press-formed product can be reduced by lengthening the precooling period.

  However, when the pre-cooling period is lengthened as described above, the portion cooled from the initial stage of cooling may be rapidly cooled after being cooled from the Ar3 transformation point. That is, after the start of rapid cooling, the ratio of the austenite phase of the steel sheet is not uniform, so that quenching becomes non-uniform.

  An object of the present invention is to realize a configuration in which a hot press-formed product with higher dimensional accuracy can be manufactured with higher productivity in a hot press having an upper die and a lower die.

  As a result of intensive studies, the present inventors have found that there are mainly two causes for the cooling non-uniformity that causes the defective shape of the hot press-formed product. One of the causes of non-uniform cooling is an annular cooling unevenness centered on the coolant injection hole of the hot press die, which is also disclosed in Patent Document 1. Then, another cause of non-uniform cooling is a timing shift when the refrigerant is ejected from each refrigerant ejection hole of the hot press mold.

  For example, when hot-pressing a hat-shaped member from the steel plate 2 using the hot-pressing mold 201 shown in cross section in FIG. 11, the difference in unevenness between the surfaces of the upper mold 211 and the lower mold 221 Is d. Here, the upper mold 211 and the lower mold 221 respectively have refrigerant channels 212 and 222 formed therein, and refrigerant ejection holes 211b and 221b connected to the refrigerant channels 212 and 222 on the mold surface. Is formed. As described above, if the unevenness difference between the surfaces of the upper mold 211 and the lower mold 221 is d, the difference between the lengths of the refrigerant channels 212 and 222 connected to the refrigerant ejection holes 211b and 221b is also d. .

  If it does so, a shift | offset | difference will arise in the timing which a refrigerant | coolant ejects from each refrigerant | coolant ejection hole 211b, 221b by the time which a refrigerant | coolant moves through d which is the difference of the length of the refrigerant flow paths 212,222. When such a shift in the refrigerant ejection timing occurs, in the steel sheet molded product after the steel plate 2 has been hot-pressed, the portion where the refrigerant is ejected at an earlier timing contracts first. As a result, the hot press-formed product is warped so that the portion cooled at an early timing is on the inside and the portion cooled at a later timing is on the outside.

  In FIG. 11, reference numeral 5 denotes a flow rate adjustment valve for adjusting the flow rate of the cooling water in the refrigerant channel 212 in the upper mold 211. Reference numeral 6 denotes a flow rate adjusting valve for adjusting the flow rate of the cooling water in the refrigerant flow path 222 in the lower mold 221.

  As shown in FIG. 13, when hot press-molding a hot press-formed product 203 having a hat-like cross section and a shape that is long in one direction, a hot press mold is also used in the longitudinal direction of the hot press-formed product 203. There are cases where the lengths of the refrigerant flow paths formed in are different (see FIG. 12). Therefore, when cooling the steel sheet molded product, the cooling timing is shifted in the longitudinal direction of the steel sheet molded product. Therefore, when the refrigerant is supplied from only one of the lower mold and the upper mold, warpage occurs in the longitudinal direction of the hot press-formed product 203 as indicated by an arrow in FIG.

  FIG. 12 is a perspective view of the hot press die 201 shown in FIG. When the coolant is supplied from both the upper mold 211 and the lower mold 221 using the hot press mold 201 shown in FIGS. 11 and 12, the cooling timing deviation of the hot press molded product is increased. The mold 211 and the lower mold 221 are different. For this reason, the respective cooling timings in the upper mold 211 and the lower mold 221 are offset, and the warp generated in the hot press-formed product 203 is reduced.

  Therefore, by supplying the coolant from both the upper mold 211 and the lower mold 221 to the steel sheet molded product, there is a warp due to the difference in cooling timing, but the difference in cooling timing between the upper and lower surfaces of the steel sheet molded product. Can be reduced, and the cooling rate of the steel sheet molded product can be improved. Thus, cooling from both the upper mold 211 and the lower mold 221 improves the cooling rate of the steel sheet molded product, and as a result, shortens the time until the cooling of the steel sheet molded product is completed. In addition, the warpage occurring in the hot press-formed product can be reduced.

  However, even when the refrigerant is supplied from both the upper mold and the lower mold as described above, the refrigerant jet timing from each refrigerant jet hole is different, so the dimension of the hot press-molded product due to the deviation of the cooling timing. The deterioration of accuracy cannot be improved. In addition, by performing pre-cooling as disclosed in Patent Document 1 for a long time, when the timing of the rapid cooling start by the main cooling is matched, a location that is cooled at a temperature lower than the Ar3 transformation point at the start of the rapid cooling occurs, It may cause quenching unevenness.

  Based on the above points, as a result of careful consideration, the present inventors have considered that if the refrigerant reaches the vicinity of the refrigerant ejection hole in each refrigerant flow channel at the start of cooling of the steel sheet molded product, the refrigerant from each refrigerant ejection hole It has been found that there is no shift in the supply timing and no cooling timing in the steel sheet molded product. Further, the present inventors, as long as the refrigerant reaches the vicinity of the refrigerant ejection hole in each refrigerant flow path as described above, even when performing pre-cooling as disclosed in Patent Document 1, Therefore, it was considered that the pre-cooling could be quickly switched to the main cooling.

  Therefore, in the present invention, in order to realize the above-mentioned idea, an on-off valve is provided in the refrigerant flow path in the hot press die, and the on-off valve is closed before cooling the steel sheet molded product. By filling the coolant to a predetermined position in the flow path, the supply timing of the coolant supplied from each coolant ejection hole is matched when the cooling of the steel sheet molded product is started.

  Specifically, in the hot pressing die according to an embodiment of the present invention, a plurality of refrigerant flow paths are formed therein, and outlets of the plurality of refrigerant flow paths are formed on a contact surface with the steel plate. A mold main body having a plurality of refrigerant jet holes formed therein, and an on-off valve provided in each of the plurality of refrigerant flow paths in the mold main body (first configuration).

  In a hot press mold, by providing on / off valves in the plurality of refrigerant flow paths formed in the mold, the deviation of the timing of supplying the refrigerant to the steel sheet molded product at the start of cooling of the steel sheet molded product is suppressed. It becomes possible to do. That is, in the hot press mold, it is possible to store the refrigerant in the refrigerant flow path by providing the on-off valve in the refrigerant flow path. This makes it possible to synchronize the timing of supplying the coolant from the plurality of refrigerant flow paths to the steel plate molded product at the start of cooling of the steel plate molded product.

  Therefore, with the above-described configuration, it is possible to suppress uneven cooling when the steel sheet molded product is cooled. Therefore, the deterioration of the dimensional accuracy of the hot press-formed product formed by hot press forming can be suppressed.

  Moreover, even when pre-cooling and main cooling are performed as in the configuration disclosed in Patent Document 1, the above-described configuration makes it possible to match the timing of supplying the refrigerant from each refrigerant flow path. Therefore, it is not necessary to lengthen the pre-cooling period in order to match the main cooling timing. Therefore, it can prevent that the cooling period of hot press molding becomes long. Therefore, the productivity of hot press molding can be improved. Further, when the pre-cooling period is long, the steel sheet is cooled to a temperature lower than the Ar3 transformation point, so that a problem arises that a hot press-formed product having a predetermined hardness cannot be obtained. Such a problem can also be avoided by shortening the pre-cooling period.

  In the first configuration, the on-off valve is provided in a range of a predetermined distance from the refrigerant ejection hole in the plurality of refrigerant flow paths (second configuration).

  By providing an on-off valve within a predetermined distance from the refrigerant ejection hole in the refrigerant flow path, the timing for supplying the refrigerant from the refrigerant flow path is matched with the timing for supplying the refrigerant from the other refrigerant flow paths. A refrigerant can be stored in the refrigerant flow path. Thereby, the timing which supplies a refrigerant | coolant from a some refrigerant | coolant flow path can be match | combined, and generation | occurrence | production of the cooling nonuniformity at the time of cooling a steel plate molded product can be suppressed.

  Here, the range of the predetermined distance from the refrigerant ejection hole in the refrigerant flow path means that the timing of supplying the refrigerant from the refrigerant flow path by storing the refrigerant in the refrigerant flow path by the open / close valve from the other refrigerant flow paths. It means the position of the on-off valve that can be matched with the timing of supplying the refrigerant. The position is preferably in the vicinity of the nozzle provided at the outlet portion of the refrigerant ejection hole. This is because it is easy to install an on-off valve close to the refrigerant ejection hole and in the refrigerant flow path.

  In the first or second configuration, the on-off valve is opened when the refrigerant pressure upstream of the on-off valve is equal to or higher than a predetermined pressure value in the refrigerant flow path provided with the on-off valve. (Third configuration)

  Thereby, at the start of cooling of the steel sheet molded product, when the refrigerant is supplied into the refrigerant channel and the pressure of the refrigerant in the refrigerant channel exceeds a predetermined pressure value, the opening and closing of the on-off valve in the refrigerant channel is controlled. Without this, the on-off valve is opened, and the coolant can be supplied from the coolant channel to the steel sheet molded product. Accordingly, since a driving device or a control device for performing opening / closing control of the opening / closing valve is not required, a structure for supplying a refrigerant from the hot press die to the steel sheet molded product can be realized with a simple and inexpensive configuration.

  A hot press machine according to an embodiment of the present invention includes the hot press die according to any one of the first configuration to the third configuration. The hot pressing mold is an upper mold (fourth configuration).

  When a hot press die is used as the upper die, the refrigerant tends to flow out of the refrigerant flow path due to gravity. By providing an opening / closing valve on the outlet side of the plurality of refrigerant channels formed inside the upper mold, it becomes possible to store the refrigerant in the refrigerant channel. Therefore, at the start of cooling of the steel sheet molded product, it is possible to match the timing of supplying the coolant to the steel sheet molded product from the plurality of refrigerant flow paths in the hot press mold.

  As described above, when the hot pressing mold of the first configuration to the third configuration is used as the upper mold of the hot press machine, the refrigerant flows out from the refrigerant flow path of the upper mold. Therefore, it is effective to apply the present invention.

  The method for manufacturing a hot press-formed product according to an embodiment of the present invention is a method for manufacturing a hot press-formed product using a hot press machine having a fourth configuration. A preparation step of closing the on-off valve with the refrigerant filled in the plurality of refrigerant flow paths, and hot pressing the steel plate using the hot pressing mold, A hot pressing step to obtain, and a quenching step of simultaneously jetting refrigerant from a plurality of refrigerant jet holes formed in the hot press die in a state where the steel sheet molded product is clamped (first method) ).

  Thereby, since a refrigerant | coolant can be ejected simultaneously from the refrigerant | coolant ejection hole of a hot press metal mold | die with respect to a steel plate molded product, it suppresses that a cooling nonuniformity arises when cooling a steel plate molded product with a refrigerant | coolant. Can do. Therefore, a hot press-formed product in which deterioration of dimensional accuracy due to uneven cooling is suppressed by the above-described manufacturing method can be obtained.

  Here, the refrigerant is simultaneously ejected from the plurality of refrigerant ejection holes is slightly shifted if the timing of ejecting the refrigerant from the plurality of refrigerant ejection holes is such that the dimensional accuracy of the hot press-formed product is acceptable. Including cases.

  In the first method, the hot press has a refrigerant flow path formed therein, and a plurality of refrigerant ejection holes which are outlets of the plurality of refrigerant flow paths are formed on a contact surface with the steel plate. A formed lower mold is provided. In the preparation step and the hot pressing step, a refrigerant is supplied into the refrigerant flow path of the lower mold at a predetermined pressure or a predetermined flow rate. In the quenching step, the refrigerant is simultaneously ejected from the plurality of refrigerant ejection holes formed in the hot press mold and the plurality of refrigerant ejection holes formed in the lower mold (second method).

  As a result, when the steel sheet molded product obtained in the hot pressing process is cooled, it is formed on the upper mold (hot press mold) and lower mold of the hot press machine, respectively. The refrigerant can be simultaneously supplied from the formed refrigerant ejection holes. Therefore, when cooling a steel plate molded product with a refrigerant | coolant, it can suppress more reliably that a cooling nonuniformity arises. Therefore, a hot press-formed product in which deterioration of dimensional accuracy due to uneven cooling is suppressed by the above-described manufacturing method can be obtained.

  According to the hot press die according to an embodiment of the present invention, a plurality of refrigerant flow paths are provided inside, and an open / close valve is provided in the plurality of refrigerant flow paths. Thereby, the structure of the hot press die which can manufacture a hot press-formed product with higher dimensional accuracy with higher productivity can be realized.

FIG. 1 is a cross-sectional view showing a schematic configuration of a hot press die according to Embodiment 1 of the present invention. FIG. 2 is a perspective view showing a schematic configuration of a hot press die according to Embodiment 1 of the present invention. FIG. 3 is a perspective view of a hot press-formed product formed using the hot press die according to Embodiment 1 of the present invention. FIG. 4 is a diagram schematically illustrating a state in which the refrigerant is stored in the refrigerant flow path of the hot press mold according to the first embodiment of the present invention by an on-off valve. FIG. 5 is a diagram schematically showing how a steel plate molded product is cooled by a refrigerant in hot press forming. FIG. 6 is a diagram showing a schematic configuration of a control device for a hot press machine according to an embodiment of the present invention. FIG. 7 is a flowchart showing an outline of the operation of the hot press according to the embodiment of the present invention. FIG. 8 is a flowchart showing an outline of the operation of the hot press according to the embodiment of the present invention. FIG. 9 is a flowchart showing an outline of the operation of the hot press machine according to the embodiment of the present invention. FIG. 10: is sectional drawing which shows schematic structure of the lower die of the hot press die concerning Embodiment 2 of this invention. FIG. 11 is a view corresponding to FIG. 1 showing a schematic configuration of a conventional hot pressing die. FIG. 12 is a view corresponding to FIG. 2 showing a schematic configuration of a conventional hot pressing die. FIG. 13 is a diagram schematically showing warpage occurring in a hot press-formed product when a refrigerant is supplied from only one of a lower die and an upper die in a conventional hot press die. .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the dimension of the structural member in each figure does not represent the dimension of an actual structural member, the dimension ratio of each structural member, etc. faithfully.

<Embodiment 1>
(Configuration of hot press mold)
FIG.1 and FIG.2 is a figure which shows schematic structure of the hot press 1 which concerns on Embodiment 1 of this invention. The hot press machine 1 includes an upper die 11 (hot press die, die main body) and a lower die 21. By using this hot press machine 1, hot press forming for hot forming a steel plate is realized.

  Specifically, the heated steel plate 2 is sandwiched between the upper die 11 and the lower die 21 so that the steel plate 2 is hot-formed. Then, the steel plate molded product is cooled as it is with the upper mold 11 and the lower mold 21 as it is, and quenching is performed, and the hot press-formed product 3 having predetermined material characteristics (strength and hardness) ( FIG. 3) is obtained.

  In addition, FIG. 1 has shown the schematic structure of the hot press machine 1 used when shape | molding the hot press molded product 3 of a cross-sectional hat shape in a cross section. For the sake of explanation, FIG. 2 is a perspective view of a part of the configuration of the hot press machine 1 (refrigerant flow paths 12, 22 and refrigerant supply paths 13, 23, etc. described later). The following description is based on the configuration of FIGS. 1 and 2, but the configuration of the present embodiment may be applied to a hot press machine and a mold for molding a hot press-formed product other than a hat-shaped cross section.

  The upper mold 11 has an upper mold body 15 and an on-off valve 31 in a refrigerant flow path 12 to be described later. The lower mold 21 includes a lower mold main body 25 and an opening / closing valve 31 in a refrigerant flow path 22 described later. The refrigerant flow path 12 is inside the upper mold body 15. The refrigerant flow path 22 is inside the lower mold body 25. That is, the on-off valve 31 is inside the upper mold body 15 and the lower mold body 25, respectively.

  As shown in FIGS. 1 and 2, the upper mold body 15 and the lower mold body 25 have a long shape in one direction (the paper surface direction in FIG. 1). The upper mold body 15 has a concave portion 11a in the center portion in the width direction (lateral direction in FIG. 1). The recess 11 a is formed in a groove shape extending in the longitudinal direction of the upper mold body 15. That is, the upper mold 11 is a female mold.

  The lower mold body 25 swells upward at the central portion in the width direction so as to form a hat-shaped space having a gap corresponding to the thickness of the steel plate 2 or a predetermined gap between the lower mold body 25 and the upper mold body 15. It has the bulging part 21a to protrude. The bulging portion 21a is arranged to face the recess 11a so as to correspond to the recess 11a of the upper mold body 15 in a state where the upper mold 11 and the lower mold 21 are combined. That is, the bulging portion 21 a also extends in the longitudinal direction of the lower mold body 25. Therefore, the lower mold 21 is a male mold.

  The upper mold 11 may be a male mold and the lower mold 21 may be a female mold without being limited to the above-described configuration.

  The upper mold body 15 and the lower mold body 25 have contact surfaces 11c and 21c that come into contact with the steel plate 2 on the side where the steel plate 2 is sandwiched. That is, the steel plate 2 is formed in a cross-sectional hat shape by being sandwiched between the contact surfaces 11c and 21c.

  Although not particularly illustrated, the upper mold body 15 and the lower mold body 25 have minute irregularities on the contact surfaces 11c and 21c that are in contact with the steel plate 2. By providing such irregularities on the contact surfaces 11c and 21c of the upper mold body 15 and the lower mold body 25, the refrigerant flow path 12 provided in the upper mold body 15 and the lower mold body 25 as described later. , 22 can flow between the upper mold 11 and the steel plate 2 and between the lower mold 21 and the steel plate 2.

  As shown in FIGS. 1 and 2, a plurality of refrigerant flow paths 12 and 22 are provided inside the upper mold body 15 and the lower mold body 25, respectively. When the hot press machine 1 performs hot press forming of the steel plate 2, these coolant channels 12 and 22 supply a coolant for rapidly cooling the steel plate molded product obtained by forming the steel plate 2. It is a flow path for. Here, the refrigerant may be any liquid as long as it is a liquid that can cool the steel sheet molded product, such as cooling water.

  The refrigerant flow paths 12 and 22 are formed so as to be connected to the refrigerant supply paths 13 and 23 provided in the upper mold main body 15 and the lower mold main body 25, respectively. The refrigerant supply paths 13 and 23 are respectively provided in the upper mold body 15 and the lower mold body 25 so as to extend in the width direction. A plurality of refrigerant flow paths 12 and 22 are connected to the refrigerant supply paths 13 and 23, respectively (see FIG. 1).

  The refrigerant supply paths 13 and 23 are each connected to a pump (not shown) provided outside the hot press 1 via a pipe 4. The pump supplies cooling water stored in an external water storage tank or the like (not shown) to the pipe 4. Thereby, the refrigerant flow paths 12 and 22 are connected to the external water storage tank etc. via the refrigerant supply paths 13 and 23 and the piping 4, respectively, and cooling water is supplied from the water storage tank etc. by a pump. . In FIG. 1, reference numeral 5 denotes a flow rate adjustment valve for adjusting the flow rate of the cooling water in the refrigerant flow path 12 in the upper mold 11. Reference numeral 6 denotes a flow rate adjusting valve for adjusting the flow rate of the cooling water in the refrigerant flow path 22 in the lower mold 21.

  The refrigerant flow paths 12 and 22 have outlets on the surfaces of the upper mold body 15 and the lower mold body 25, respectively. That is, in the upper mold body 15 and the lower mold body 25, the refrigerant (cooling water in the present embodiment, hereinafter) is supplied to the contact surfaces 11 c and 21 c in contact with the steel plate 2 from the refrigerant channels 12 and 22. Then, the refrigerant is described as cooling water.) Refrigerant ejection holes 11b and 21b are formed as outlets for ejecting the refrigerant.

  The coolant flow paths 12 and 22 are formed in the upper mold body 15 and the lower mold body 25 so that the coolant ejection holes 11b and 21b are located at locations where the steel sheet molded product needs to be cooled during hot press forming. Is done. Moreover, the refrigerant flow paths 12 and 22 may be provided so that it may branch from one piping according to the formation position of the refrigerant jet holes 11b and 21b. In FIG. 1, the branch flow paths of the refrigerant flow paths 12 and 22 are denoted by reference numerals 12a and 22a.

  There are on-off valves 31 in the refrigerant flow paths 12 and 22, respectively. In the present embodiment, there are on-off valves 31 in all the refrigerant flow paths 12 and 22 formed in the upper mold body 15 and the lower mold body 25, respectively. The on-off valve 31 is provided within a predetermined distance from the refrigerant ejection holes 11b and 21b in the refrigerant flow paths 12 and 22, respectively. The range of the predetermined distance is such that the refrigerant is stored in the refrigerant flow paths 12 and 22 by the on-off valve 31 as will be described later, and the timing for supplying the refrigerant from the refrigerant flow paths 12 and 22 is set to the other refrigerant flow paths 12. , 22 means the position of the on-off valve 31 that can be matched with the timing of supplying the refrigerant.

  The range of the predetermined distance from the refrigerant ejection holes 11b and 21b is preferably a position as close as possible to the refrigerant ejection holes 11b and 21b. For example, when nozzles (not shown) are provided in the refrigerant ejection holes 11b and 21b, it is preferable to provide the on-off valve 31 so as to be adjacent to the upstream side of the nozzles.

  The on-off valve 31 may be a check valve, for example. The check valve is provided in the refrigerant flow paths 12 and 22 so that the refrigerant does not flow in the direction opposite to the direction in which the refrigerant is supplied from the refrigerant ejection holes 11b and 21b. That is, in FIGS. 1 and 2, when a check valve is provided in the refrigerant flow path 12 in the upper mold body 15, the check valve stops the refrigerant flow upward in the refrigerant flow path 12. It is arranged in the upper mold body 15. When a check valve is provided in the refrigerant flow path 22 in the lower mold body 25, the check valve is disposed in the lower mold main body 25 so as to stop the flow of the refrigerant downward in the refrigerant flow path 22.

  Further, the check valve is configured to be opened when a pressure equal to or higher than a predetermined pressure value is applied in a direction in which the flow of the refrigerant is permitted (a direction in which the refrigerant flows through the refrigerant ejection holes 11b and 21b). In general, the check valve is urged so that a valve body (not shown) closes the flow path by a spring, and the valve body is displaced against the urging force of the spring by the flow of refrigerant from one direction. In some cases, fluid is allowed to flow in the flow path. In the present embodiment, when a check valve is used as the on-off valve 31, the spring for urging the valve body has a refrigerant pressure in the refrigerant flow paths 12 and 22 on the upstream side of the check valve equal to or higher than a predetermined pressure value. In this case, the urging force is adjusted so as to be in the open state.

  Here, the predetermined pressure value is a value larger than the pressure generated by its own weight when the refrigerant accumulates in the refrigerant flow paths 12 and 22 provided with the check valves. By configuring the check valve so as to be opened at a predetermined pressure value or more, the check valve can be prevented from being opened by the refrigerant accumulated in the refrigerant flow paths 12 and 22. Thereby, it is not necessary to control opening and closing of the valve, and the refrigerant can be stored in the refrigerant flow path 12 of the upper mold 11 by a check valve having a simple configuration.

  The on-off valve 31 is not limited to the check valve described above, and is not opened due to the pressure of the refrigerant in the refrigerant flow passages 12 and 22, and can be switched to the open state at the start of cooling the steel sheet molded product. Any valve may be used as long as it is a simple valve. Further, the valve is not limited to a valve that can be switched between an open state and a closed state by a pressure change in the refrigerant flow path, and may be a valve that can be controlled to open and close by a control device or the like.

  Since the on-off valve 31 having the above configuration is in the refrigerant flow paths 12 and 22, in the refrigerant flow paths 12 and 22, in the vicinity of the refrigerant ejection holes 11 b and 21 b of the upper mold 11 and the lower mold 21 ( The refrigerant can be accumulated up to a predetermined distance from the refrigerant ejection hole. As an example, FIG. 4 schematically shows a state in which the coolant is accumulated in the coolant channel 12 up to the vicinity of the coolant ejection hole 11b in the upper mold 11.

  Thus, in the hot press forming, when the refrigerant is supplied from the respective refrigerant flow paths 12 and 22 to the steel sheet molded product via the refrigerant ejection holes 11b and 21b, the same timing is applied from the respective refrigerant flow paths 12 and 22. A refrigerant can be supplied. That is, when cooling of the steel sheet molded product is started, the pressure and the refrigerant flow rate in the refrigerant flow paths 12 and 22 are controlled by the pump and the flow rate adjusting valves 5 and 6 (not shown), so that the same timing from the refrigerant injection holes 11b and 21b. A refrigerant is supplied to the steel sheet molded product.

  Therefore, since the steel plate molded product can be uniformly cooled, it is possible to suppress deterioration in dimensional accuracy of the hot press-formed product 3 due to uneven cooling.

  The operation of the hot press 1 having the above-described configuration is controlled by the control device 40. FIG. 6 shows a block diagram of a schematic configuration of the control device 40. The control device 40 performs drive control of the hot press machine 1. The control device 40 includes a mold control unit 41, a steel plate movement control unit 42, a cooling water control unit 43, a mold position detection unit 45, a steel plate position detection unit 46, and a timer 47.

  The mold control unit 41 moves the upper mold 11 up and down relative to the lower mold 21. That is, when pressing the steel plate 2, the upper mold 11 is moved downward so as to be closer to the lower mold 21. On the other hand, when the hot press molded product 3 is taken out from between the upper mold 11 and the lower mold 21, the upper mold 11 is moved upward so as to be separated from the lower mold 21. The mold control unit 41 controls the vertical movement of the upper mold 11 by outputting a signal to a drive device (not shown) of the upper mold 11.

  The mold position detector 45 detects that the upper mold 11 is at the bottom dead center. That is, the mold position detection unit 45 outputs a bottom dead center detection signal when the upper mold 11 is at the bottom dead center. The bottom dead center detection signal output from the mold position detection unit 45 is input to the mold control unit 41. When moving the upper mold 11 to the bottom dead center, the mold control unit 41 moves the upper mold 11 downward until a bottom dead center detection signal is input from the mold position detection unit 45.

  The steel plate movement control unit 42 controls the movement of the steel plate 2 and the hot press-formed product 3 with respect to the upper mold 11 and the lower mold 21. That is, the steel plate movement control unit 42 moves the steel plate 2 between the upper die 11 and the lower die 21 before hot pressing the steel plate 2 with the upper die 11 and the lower die 21. Further, the steel plate movement control unit 42 moves the hot press-formed product 3 between the upper die 11 and the lower die 21 after obtaining the hot press-formed product 3 from the steel plate 2 by hot press forming. . The steel plate movement control unit 42 controls the movement of the steel plate 2 and the hot press-formed product 3 by outputting a signal to a conveying device (not shown).

  The steel plate position detection unit 46 detects that the steel plate 2 is in a press position (a predetermined position where the steel plate 2 is press-formed by the upper mold 11 and the lower mold 21). That is, the steel plate position detector 46 outputs a press position detection signal when the steel plate 2 is in the press position. The press position detection signal output from the steel plate position detection unit 46 is input to the steel plate movement control unit 42. When moving the steel plate 2 to the press position, the steel plate movement control unit 42 moves the steel plate 2 until a press position detection signal is input from the steel plate position detection unit 46.

  The cooling water control unit 43 controls the supply of cooling water to the upper mold 11 and the lower mold 21. The cooling water control unit 43 outputs a signal for instructing the supply amount of cooling water to a pump (not shown) and the flow rate adjusting valves 5 and 6.

  Specifically, the cooling water control unit 43 starts the supply of the cooling water and continues until the coolant channels 21 and 22 of the upper mold 11 and the lower mold 21 are filled with the cooling water. A signal (for example, a signal indicating that the pump rotation is ON and the flow rate adjustment valve opening is small) is output so that a small amount of cooling water is supplied to the lower mold 21. On the other hand, the cooling water control unit 43 cools the coolant channels 12 and 22 of the upper mold 11 and the lower mold 21 in a state where the steel plate molded product is pressed by the upper mold 11 and the lower mold 21. A signal (for example, a signal indicating that the pump rotation is ON and the flow rate adjustment valve is large) is output so as to increase the amount of water supplied. Further, the cooling water control unit 43 outputs a stop signal so as to stop the supply of the cooling water to the upper mold 11 and the lower mold 21 when the time measured by the timer 47 described later has passed for a predetermined time. To do.

  The timer 47 counts time from the time when the cooling water control unit 43 starts supplying cooling water. Specifically, the timer 47 is in a state where the cooling water control unit 43 instructs the supply of the cooling water to the refrigerant flow paths 12 and 22 of the upper mold 11 and the lower mold 21 in the preparation state, and the upper mold. From the time when a signal for increasing the amount of cooling water supplied to the refrigerant flow paths 12 and 22 is output from the cooling water control unit 43 in a state where the steel sheet molded product is pressed by the mold 11 and the lower mold 21, respectively. Count the elapsed time.

  In addition, the timer 47 is used when the time counted from the time when the supply of the cooling water to the refrigerant flow paths 12 and 22 is instructed in the preparatory state has passed a certain time, or the cooling supplied to the refrigerant flow paths 12 and 22 A signal is output to the cooling water control unit 43 when a predetermined time has elapsed after outputting a signal for increasing the amount of water supply. When the signal is input from the timer 47, the cooling water control unit 43 outputs a signal for stopping the supply of the cooling water (for example, a signal indicating that the pump rotation is OFF or the flow rate adjustment valve opening is closed).

  The timer 47 resets the counted time when the coolant supply stop signal is output from the coolant control unit 33.

  Here, the predetermined time is set to a cooling water supply time such that the coolant channels 12 and 22 are filled with the cooling water. Further, the predetermined time is set to a cooling time of the steel sheet molded product so that a hot press-formed product 3 having predetermined material characteristics is obtained.

(Method for manufacturing hot press-formed products)
Next, a method for obtaining the hot press-formed product 3 using the hot press 1 having the above-described configuration will be described with reference to FIGS. FIG. 7 is a flow including a preparation process. FIG. 8 is a flow including a hot pressing process performed after the preparation process. FIG. 9 is a flow including a quenching process performed after the hot pressing process.

  First, when the flow shown in FIG. 7 is started (start), the cooling water control unit 43 of the control device 40 instructs the opening / closing valve 31 in the upper mold 11 and the lower mold 21 to be in an open state (the opening signal is given). Output) (step S1).

  In subsequent step S2, the cooling water control unit 43 supplies a small amount of cooling water to the coolant flow paths 12 and 22 of the upper mold 11 and the lower mold 21 and pumps and flow rate adjusting valves 5 and 6 (not shown). Instruct (signal output). Specifically, the cooling water control unit 43 outputs an ON signal to the pump and outputs a small opening signal to the flow rate adjusting valves 5 and 6.

  When the cooling water control unit 43 outputs a signal in step S2, the timer 47 starts measuring time (step S3). In step S4, it is determined whether the time measured by the timer 47 has passed a certain time.

  If it is determined in step S4 that the fixed time has elapsed (in the case of YES), the process proceeds to step S5 and the subsequent steps, and after closing the on-off valve 31, the steel plate 2 is moved between the upper mold 11 and the lower mold 21. It is moved to a press position (a predetermined position where the steel plate 2 is press-formed by the upper mold 11 and the lower mold 21). On the other hand, if it is determined in step S4 that the fixed time has not elapsed (NO), the determination in step S4 is repeated until it is determined in step S4 that the fixed time has elapsed.

  Here, the predetermined time is set to a cooling water supply time such that the coolant channels 12 and 22 are filled with the cooling water. Therefore, when the time measured by the timer 47 reaches the predetermined time, the refrigerant is flowing out from the refrigerant ejection hole 11 b of the upper mold 11.

  In step S5, the cooling water control unit 43 instructs the on-off valve 31 to close (outputs a close signal). Thereby, the state where the refrigerant flow path 12 in the upper mold 11 is filled with the cooling water is maintained (see FIG. 4). In step S6, the cooling water control unit 43 closes the flow rate adjusting valves 5 and 6 to stop the supply of the cooling water to the refrigerant flow paths 12 and 22 of the upper mold 11 and the lower mold 21. Is output. Thereafter, in step S7, the steel plate movement control unit 42 gives an instruction (signal output) to the conveying device (not shown) of the steel plate 2 so as to move the steel plate 2 to the press position.

  In subsequent step S8, the steel plate position detection unit 46 determines whether or not the steel plate 2 is in the press position, that is, whether a press position detection signal is output from the steel plate position detection unit 46. In step S8, when it is determined that the steel plate 2 is in the press position (in the case of YES), the process proceeds to step S9 and subsequent steps, and the upper mold 11 is moved downward. On the other hand, when it is determined in step S8 that the steel plate 2 is not in the press position (in the case of NO), the process returns to step S7 and instructs the conveying device to move the steel plate 2 to the press position again. (Signal output).

  In addition, the state (X in FIG.7 and FIG.8) of the hot press machine 1 after step S9 is a preparation state before the hot press and the upper die 11 and the lower die 21 are separated. . In this preparatory state, the steel plate 2 is in the press position, and the refrigerant flow path 12 of the upper mold 11 is filled with cooling water. Moreover, there is almost no dripping of the cooling water with respect to the steel plate 2 from the refrigerant | coolant ejection hole 11b.

  In step S9 which proceeds after it is determined in step S8 that the steel plate 2 is in the press position, the mold control unit 41 moves the upper mold 11 to a driving device (not shown) so as to move the upper mold 11 downward. An instruction (signal output) is given to the terminal. Thereby, the steel plate 2 is hot-pressed between the upper mold 11 and the lower mold 21.

  In subsequent step S10, the mold position detection unit 45 determines whether or not the position of the upper mold 11 is the bottom dead center, that is, whether or not a bottom dead center detection signal is output from the mold position detection unit 45. . In this step S10, when it is determined that the position of the upper mold 11 is the bottom dead center (in the case of YES), the process proceeds to step S11 and the refrigerant flow paths of the upper mold 11 and the lower mold 21. Increase the amount of cooling water supplied to 12 and 22.

  On the other hand, if it is determined in step S10 that the position of the upper mold 11 is not at the bottom dead center (in the case of NO), the process returns to step S9 to again instruct the drive device for the upper mold 11 (Signal output). Steps S9 and S10 are repeated until it is determined in step S10 that the upper mold 11 is at the bottom dead center.

  In addition, the state (Y in FIG.8 and FIG.9) of the hot press 1 after step S10 is the state which clamped the steel plate molded product between the upper metal mold | die 11 and the lower metal mold | die 21. FIG. In this clamped state, the steel plate 2 is a steel plate molded product in a state of being pressed between the upper die 11 and the lower die 21.

  As shown in FIG. 9, in step S11, the cooling water control unit 43 moves the flow control valves 5 and 6 upward so that the refrigerant is ejected from the refrigerant ejection holes 11b and 21b of the upper mold 11 and the lower mold 21. An instruction to increase the amount of cooling water supplied to the coolant flow paths 12 and 22 of the mold 11 and the lower mold 21 (signal output of a large amount of cooling water) is issued. Specifically, the cooling water control unit 43 outputs a signal indicating a large opening degree to the flow rate adjusting valves 5 and 6.

  In subsequent step S <b> 12, the cooling water control unit 43 issues an opening instruction (outputs an opening signal) to the on-off valves 31 of the upper mold 11 and the lower mold 21. As a result, cooling water is ejected from the coolant ejection holes 11b and 21b of the upper mold 11 and the lower mold 21 toward the steel plate molded product. Since the coolant flow paths 12 and 22 of the upper mold 11 and the lower mold 21 are filled with cooling water, when the on-off valve 31 is opened in step S12, as shown in FIG. 5, the upper mold 11 and the lower mold Cooling water is ejected simultaneously and quickly from the coolant ejection holes 11b and 21b of the mold 21.

  Next, in step S <b> 13, the timer 47 measures the time that has elapsed since the cooling water control unit 43 issued an instruction (signal output) to increase the amount of cooling water supplied. In a succeeding step S14, it is determined whether or not the time measured by the timer 47 has passed a predetermined time.

  Here, the predetermined time is set to a cooling time of the steel sheet molded product so that a hot press-formed product 3 having predetermined material characteristics is obtained.

  If it is determined in step S14 that the time measured by the timer 47 has passed the predetermined time (in the case of YES), the process proceeds to step S15, where the cooling water control unit 43 performs the upper mold 11 and the lower mold 21. An instruction (stop signal output) to stop the supply of cooling water to is performed. Specifically, the cooling water control unit 43 outputs a close signal to the flow rate adjusting valves 5 and 6. If the next steel plate 2 is not hot-press formed, the cooling water control unit 43 outputs an OFF signal to the pump in step S15.

  On the other hand, if it is determined in step S14 that the time measured by the timer 47 has not passed the predetermined time (in the case of NO), the process proceeds to step S14 until it is determined in step S14 that the predetermined time has passed. Repeat the determination.

  In step S <b> 16 that proceeds after the supply of cooling water to the upper mold 11 and the lower mold 21 is stopped in step S <b> 15, the mold control unit 31 raises the upper mold 11 relative to the lower mold 21. An instruction (signal output) is given to the driving device of the upper mold 11. Thereby, the upper mold 11 and the lower mold 21 are separated from each other.

  In subsequent step S <b> 17, the steel plate movement control unit 42 gives an instruction (signal output) to the conveying device so as to move the hot press-formed product 3 in the lateral direction from between the upper mold 11 and the lower mold 21. Do. Thereby, the hot press molded product 3 can be taken out from the hot press 1. Thereafter, this flow is ended (End).

  In addition, when hot-pressing the steel plate 2 continuously by the hot press 1, the on-off valves 31 of the upper mold 11 and the lower mold 21 are closed in step S15, and the flow is started from step S7. Just restart.

  When the on-off valve 31 is a check valve, the opening degree of the valve cannot be controlled, and the forward direction (the direction of flow from the pump toward the refrigerant ejection holes 11b and 21b in the refrigerant flow paths 12 and 22). ), The cooling water flows, so steps S1, S5 and S12 are unnecessary.

  Here, cooling water is supplied into the refrigerant flow paths 12 and 22 of the upper mold 11 and the lower mold 21 so that the on-off valve 31 is closed in a state where the refrigerant flow paths 12 and 22 are filled with the cooling water. Step S5 to be performed corresponds to the preparation process. When the on-off valve is a check valve, step S5 is unnecessary, and step S6 for outputting a close signal to the flow rate adjusting valves 5 and 6 corresponds to the preparation process.

  Further, step S9 for hot pressing the steel plate 2 between the upper die 11 and the lower die 21 by moving the upper die 11 toward the lower die 21 corresponds to the hot pressing step. . Further, in a state where the steel plate molded product is clamped between the upper mold 11 and the lower mold 21, the amount of cooling water supplied to the coolant channels 12 and 22 of the upper mold 11 and the lower mold 21 is increased. By doing so, step S12 in which cooling water is jetted from the coolant ejection holes 11b, 21b of the upper mold 11 and the lower mold 21 to the steel sheet molded product corresponds to the quenching process.

  In this manufacturing method, since the on-off valve 31 is closed when the supply of the refrigerant to the steel sheet molded product is started, the refrigerant is supplied to the refrigerant flow paths 12 and 22 to the vicinity of the refrigerant ejection holes 11b and 21b. Is accumulated. Thereby, a refrigerant | coolant can be simultaneously supplied with respect to a steel plate molded product from each refrigerant | coolant flow paths 12 and 22 at the time of the cooling start of a steel plate molded product.

  Here, supplying the refrigerant at the same time includes not only the case where the refrigerant is ejected completely simultaneously from the refrigerant ejection holes 11b and 21b but also the deviation of the ejection timing to the extent that the dimensional accuracy of the hot press-formed product 3 is acceptable.

  Therefore, since the cooling timing of the steel sheet molded product can be adjusted at the start of the cooling of the steel sheet molded product after hot pressing by the above method, the dimensional accuracy of the hot press molded product 3 obtained by hot press forming. Can be prevented.

<Embodiment 2>
In the hot press machine according to the second embodiment, no opening / closing valve is provided in the refrigerant flow path in the lower mold. That is, the hot press machine according to the second embodiment is the same as the conventional lower mold (see FIG. 11) having the refrigerant flow path in the lower mold, and the timing for supplying the refrigerant into the refrigerant flow path is the same. It is different from the conventional one.

  Therefore, in the following, description of the configuration of the lower mold having the same configuration as the conventional one is omitted, and the control of the supply of the refrigerant to the refrigerant flow path in the lower mold is shown in FIGS. 7 to 9 of the first embodiment. Only the parts different from the flow will be described. Moreover, below, it demonstrates using the structure of the lower metal mold | die 221 shown in FIG. In the hot press machine according to the second embodiment, since the configuration other than the lower mold 221 is the same as that of the first embodiment, the same components as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In step S <b> 2 in FIG. 7, the cooling water control unit 43 sets the flow rate of the cooling water flowing through the refrigerant flow path 222 in the lower mold 221 to be small. Specifically, the cooling water control unit 43 outputs an ON signal to a pump (not shown) and controls the flow rate adjustment valve 6 that adjusts the flow rate of the cooling water in the refrigerant flow path 22 in the lower mold 21. A small opening signal is output.

  In step S <b> 6 in FIG. 7, the cooling water control unit 43 outputs a close signal to the flow rate adjustment valve 5 that adjusts the flow rate of the cooling water in the refrigerant flow path 12 in the upper mold 11, while the flow rate adjustment valve 6. In response to this, the output of a small opening signal is continued.

  Thereby, in the preparation state (X in FIGS. 7 and 8), the cooling water continues to flow out from the refrigerant ejection hole 221 b of the lower mold 221. At this time, since the flow rate of the cooling water flowing through the refrigerant flow path 222 of the lower mold 221 is small, the cooling water flowing out from the lower mold 221 does not hit the steel plate 2.

  In step S <b> 11 in FIG. 9, the cooling water control unit 43 sets the flow rate of the cooling water flowing through the refrigerant flow path 222 in the lower mold 221 to be large. Specifically, the cooling water control unit 43 outputs a signal indicating a large opening to the flow rate adjustment valve 6.

  In step S15 in FIG. 9, the cooling water control unit 43 prevents the cooling water from flowing out from the refrigerant ejection hole 221b of the lower mold 221 or reduces the amount of cooling water flowing out from the refrigerant ejection hole 221b. Specifically, the cooling water control unit 43 outputs a close signal or a small opening signal to the flow rate adjustment valve 6.

  In addition, when hot-pressing the steel plate 2 continuously, the amount of cooling water flowing out from the coolant ejection hole 221b of the lower mold 21 is set small in step S15 in FIG. The state in which the refrigerant is filled in the refrigerant flow path 22 of the mold 21 can be maintained until the next hot press forming of the steel plate 2. Thereby, the hot press molding of the following steel plate 2 can be performed rapidly.

  With the above configuration, the cooling water can be simultaneously ejected from the plurality of refrigerant ejection holes 221b of the lower mold 21 to the steel sheet molded product without providing an opening / closing valve in the lower mold 21. Therefore, similarly to the first embodiment, the cooling water can be ejected simultaneously from the coolant ejection holes 11b and 221b of the upper mold 11 and the lower mold 221 to the steel sheet molded product. Thereby, the effect similar to Embodiment 1 is acquired by the lower metal mold | die 221 which has an inexpensive and simple structure.

<Embodiment 3>
The hot press machine according to the third embodiment has an indirect cooling structure in which a coolant channel is provided inside as a lower die, and a coolant ejection hole for ejecting the coolant to a steel sheet molded product is not formed. A mold is used. Since this lower mold is the same as the mold of the conventional indirect cooling structure, detailed description is omitted.

  In the present embodiment, in the lower mold, unlike the lower molds 21 and 221 in the first and second embodiments, the refrigerant in the refrigerant flow paths 22 and 222 does not jet out, so it is not necessary to match the refrigerant ejection timing. Therefore, in FIGS. 7 to 9 of the first embodiment, it is not necessary to control the cooling water for the lower mold as in the first embodiment.

  Specifically, the cooling water supply instruction or the stop instruction to the lower mold in steps S2, S6, S11, and S15 of FIG. 7 is not necessary in this embodiment.

  Therefore, since the lower mold has an indirect cooling structure, the cooling capacity of the steel sheet molded product is lower than that of the upper mold. However, since the conventional mold can be used, the hot press is used in the first and second embodiments. Compared to a simpler and lower cost configuration, this can be realized.

(Other embodiments)
While the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiment, and the above-described embodiment can be appropriately modified and implemented without departing from the spirit of the invention.

  FIG. 10 shows a schematic configuration of a lower die 121 of a hot press machine according to another embodiment. In the lower mold 121, the position of the on-off valve 31 is different from that of the first embodiment. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only the portions different from those in the first embodiment are described. Note that the configuration of the upper mold is the same as that of the first embodiment, and a description thereof will be omitted.

  As shown in FIG. 10, among the plurality of refrigerant flow paths 22 formed in the lower mold body 125 of the lower mold 121, the refrigerant flow path 22 extending in the vertical direction is below the refrigerant flow path 22. An on-off valve 31 is provided (upstream). Thereby, it is possible to prevent the refrigerant from flowing backward from the refrigerant flow path 22 to the refrigerant supply path 23 due to its own weight.

  In addition, as shown in FIG. 10, among the plurality of refrigerant channels 22 formed inside the lower mold main body 125, other refrigerant channels 22 a joined to the refrigerant ejection hole 21 b that opens at the highest position are joined. In the refrigerant flow path 22, there is a possibility that the refrigerant flows backward from the refrigerant flow path 22 a connected to the refrigerant ejection hole 21 b that opens at the highest position due to its own weight. Therefore, as in the first embodiment, it is preferable to provide the opening / closing valve 31 within a predetermined distance from the refrigerant ejection hole 21b. In this case, since it is not necessary for the lower mold 121 to provide the on-off valves 31 in all the refrigerant ejection holes 21b, the manufacturing cost of the mold can be reduced.

  The present invention can be used for a hot press die used for hot press molding.

1,201 Hot press die 2 Steel plate 3, 203 Hot press molded product 11, 211 Upper die 11a Recess 11b, 21b, 211b, 221b Refrigerant injection hole 11c, 21c Contact surface 12, 22, 212, 222 Refrigerant Flow path 12a, 22a Branch flow path 13 Refrigerant supply path 15 Upper mold body (mold body)
21, 121, 221 Lower mold 21a Swelling portion 23 Refrigerant supply path 25, 125 Lower mold body 31 On-off valve

Claims (6)

A plurality of refrigerant flow paths are formed inside, and a mold body in which a plurality of refrigerant ejection holes that are outlets of the plurality of refrigerant flow paths are formed on a contact surface with the steel plate,
A hot press mold comprising: an on-off valve provided in each of the plurality of refrigerant flow paths in the mold body.   2. The hot press die according to claim 1, wherein the on-off valve is provided within a range of a predetermined distance from the refrigerant ejection hole in the plurality of refrigerant flow paths.   3. The open / close valve according to claim 1, wherein the open / close valve is opened when a refrigerant pressure upstream of the open / close valve is equal to or higher than a predetermined pressure value in the refrigerant flow path provided with the open / close valve. Hot press mold. A hot press die according to any one of claims 1 to 3,
A hot press machine, wherein the hot press mold is an upper mold. A method for producing a hot press-formed product by the hot press according to claim 4,
A preparation step of closing the on-off valve in a state where the refrigerant is filled in the plurality of refrigerant flow paths;
A hot pressing step of obtaining a steel sheet molded product by hot pressing the steel sheet using the hot pressing mold;
A method of manufacturing a hot press-formed product, comprising: a quenching step of simultaneously jetting a refrigerant from a plurality of refrigerant jet holes formed in the hot press mold in a state where the steel plate molded product is clamped. The hot press machine includes a lower mold in which a refrigerant flow path is formed and a plurality of refrigerant ejection holes that are outlets of the plurality of refrigerant flow paths are formed on a contact surface with the steel plate. Prepared,
In the preparation step and the hot pressing step, a refrigerant is supplied into the refrigerant flow path of the lower mold at a predetermined pressure or a predetermined flow rate,
6. The refrigerant according to claim 5, wherein in the quenching step, the refrigerant is simultaneously ejected from the plurality of refrigerant ejection holes formed in the hot press mold and the plurality of refrigerant ejection holes formed in the lower mold. Manufacturing method for hot press-formed products.

Images