Hot press device

Abstract

Hot pressing device (1) comprising a lower die (10) with a lower forming surface and an upper die (20) with an upper forming surface opposite the lower forming surface, which causes the lower die (10) and the upper die (20) to press a heated workpiece (W) arranged between them and that the forming surfaces thereof are simultaneously kept in contact with a surface of the workpiece (W) in order to cool the workpiece (W), wherein the improvement comprises: a trough section (14, 15, 24, 25) which extends inwards from the forming surface of the lower die (10) and / or the upper die (20), and which is formed in a part of the lower die (10) opposite an outer corner (22, 23) of the upper die (20) which acts as a working part for bending the workpiece (W), and / or in a part of the upper die (20) opposite an outer corner (12, 13) of the lower die (10) which acts as the working part; and a cooling water supply device (17, 27, 30, 50) which directs cooling water to cool the workpiece (W) to a space between the workpiece (W) and the lower die (10) and / or the upper die (20), where the trough part (14, 15, 24, 25) is formed, wherein the lower die (10) and / or the upper die (20) has a ventilation opening (18, 19, 28, 29) at the point where the trough part (14, 15, 24, 25) is formed, through which steam flows which is generated when the cooling water comes into contact with the workpiece (W), and the ventilation opening (18, 19, 28, 29) within the lower die (10) and / or the upper die (20) is formed from a surface other than the forming surface towards the space between the workpiece (W) and the lower die (10) and / or the upper die (20).

Description

Technical area

[0001] The present invention relates to a hot pressing device which simultaneously presses and cools a heated workpiece. General state of the art

[0002] Conventionally, a hot pressing device is well known which causes upper and lower dies (a pair of dies) to press a workpiece, such as a steel plate, heated to above a temperature at which an austenitic structure appears, and at the same time come into contact with the workpiece to rapidly cool or quench the workpiece.

[0003] With regard to the hot pressing device, a technology is well known which enables the dies to properly cool the workpiece during quenching by providing water channels through which cooling water flows into the interior of the dies to cool the dies (see, for example, JP 2005-7442 A).

[0004] However, due to variations in the thickness of the workpiece due to press processing, precision errors in the forming surfaces of the dies caused during die manufacturing, bending of the dies during press processing, and the like, gaps are formed between the workpiece and the dies when the workpiece is quenched. Consequently, the contact areas between the workpiece surface and the forming surfaces of the dies decrease during quenching, causing the problem that some parts of the workpiece are cooled at an insufficient cooling rate, and the hardness of the workpiece is partially lower than a predetermined value.

[0005] Furthermore, the subsequently published DE 10 2010 012 579 B3 discloses a method for producing hardened molded components, in particular structural or body components of motor vehicles, wherein a metal blank is heated, then hot-formed in the molding chamber of a hot-forming tool to form the molded component and hardened by contact with a coolant in the molding chamber of the hot-forming tool, for which purpose the coolant is fed into the molding chamber through inflow channels, wherein the state of aggregation of the coolant is adjustable.

[0006] In addition, DE 10 2007 041 013 A1 shows a hot forming tool, comprising an upper tool part and a lower tool part, which are movable relative to one another in order to transfer the hot forming tool from an open / closed tool position into a closed / open tool position, wherein the upper tool part and the lower tool part each comprise a coolable forming unit, between which a preheated semi-finished product introduced into the hot forming tool can be formed into a component in the closed tool position, wherein at least one of the forming units comprises a plurality of forming surfaces which are at least partially spaced from one another and can be placed against a surface of the semi-finished product in the closed tool position, wherein at least between some of the forming surfaces an intermediate space is formed through which a coolant can be conducted during operation of the hot forming tool.

[0007] Further relevant prior art is disclosed in JP S44-158B. Summary of the inventionProblem to be solved by the invention

[0008] The object of the present invention is to provide a hot pressing device which is capable of quenching a workpiece with a sufficient cooling rate. Means of solving the problem

[0009] The above object is achieved by the subject matter of claim 1. Advantageous developments of the invention are the subject matter of the subsequent dependent claims.

[0010] A first illustrative aspect of the present disclosure is a hot-pressing device comprising a lower die having a lower forming surface and an upper die having an upper forming surface opposite the lower forming surface, which causes the lower die and the upper die to press a heated workpiece disposed therebetween, and simultaneously maintains the forming surfaces thereof in contact with a surface of the workpiece to cool the workpiece. The hot-pressing device includes a countersinking or countersinking device.A trough part which is recessed inwardly from the forming surface of the lower die and / or the upper die, and which is formed in a part of the lower die which is opposite to a working part of the upper die for bending the workpiece, and / or a part of the upper die which is opposite to a working part of the lower die for bending the workpiece, and a cooling water supply device which supplies cooling water for cooling the workpiece to a space between the workpiece and the lower die and / or the upper die where the trough part is formed.

[0011] Preferably, the lower die and / or the upper die has, at the position where the trough part is formed, a vent passage through which steam generated when the cooling water comes into contact with the workpiece flows, and the vent passage is formed within the lower die and / or the upper die from a surface thereof other than the forming surface toward the space between the workpiece and the lower die and / or the upper die.

[0012] More preferably, the ventilation passage is formed from a surface of the lower die and / or the upper die other than the forming surface towards the trough part.

[0013] More preferably, the hot-pressing device includes a suction device that sucks the steam flowing through the ventilation passage, the suction device being connected to the ventilation passage.

[0014] Advantageously, the hot-pressing device includes a coolant supply device which supplies a coolant to the trough part, wherein the coolant supply device is arranged in the trough part. Effects of the invention

[0015] The present invention makes it possible to quench a workpiece at a sufficient cooling rate and to prevent the hardness of some parts of the workpiece from being less than a predetermined value. Short description of the figures Fig. 1 illustrates a hot pressing apparatus according to a first embodiment of the present invention. Fig. 2 is a perspective view showing a lower die of the hot pressing apparatus according to the first embodiment of the present invention. Fig. 3 represents the hot pressing device in which an upper die moves towards the bottom dead center. Fig. 4 represents the hot pressing device in which the upper die reaches the bottom dead center. Fig. 5 illustrates a hot pressing apparatus according to a second embodiment of the present invention. Fig. 6 is a perspective view showing a lower die of the hot pressing apparatus according to the second embodiment of the present invention. Description of Embodiments[First Embodiment]

[0016] The following is with reference to the Fig. 1 and Fig. 2, a hot-pressing device 1 is described as a first embodiment of a hot-pressing device according to the present invention. The hot-pressing device 1 performs hot-press forming of a workpiece W. The workpiece W corresponds to a steel plate to be pressed by the hot-pressing device 1 and is heated by ohmic heating and the like above a temperature at which an austenitic structure appears. For the sake of simplicity, Fig. 1 defines an up-down direction as an up-down direction of the hot-pressing device 1, and a right-left direction in Fig. 1 is defined as a right-left direction of the hot-pressing device 1. In addition, the Fig. 1 is defined as the front side of the hot press device 1 and the opposite side in Fig. 1 is defined as a rear side of the hot-pressing device 1, thereby defining a front-back direction of the hot-pressing device 1.

[0017] As in Fig. 1, the hot pressing device 1 includes a lower die 10 and an upper die 20 whose forming surfaces are opposite to each other, a lower water supply device 30 and a lower suction device 40 which are connected to the lower die 10, and an upper water supply device 50 and an upper suction device 60 which are connected to the upper die 20.

[0018] The lower die 10 and the upper die 20 are arranged so that their forming surfaces face each other. The upper die 20 is brought close to the lower die 10 and moved toward the bottom dead center by a hydraulic cylinder and the like. As a result, the lower die 10 and the upper die 20 press the workpiece W interposed therebetween to form the workpiece W into a so-called hat shape. At the same time, the lower die 10 and the upper die 20 keep their forming surfaces in contact with the surface of the workpiece W to cool the workpiece W. Thus, the workpiece W is manufactured as a product.

[0019] First, the general designs of the lower die 10 and the upper die 20 are described.

[0020] The lower die 10 corresponds to the upper die 20. The lower die 10 has a projection 11 protruding upward from the forming surface (the upper surface) thereof. The projection 11 protrudes upward from the forming surface of the lower die 10. The projection 11 is formed continuously in the front-backward direction at the intermediate part (essentially the middle part) in the right-left direction of the forming surface of the lower die 10.

[0021] The lower die 10 has an upper surface 10a extending in the right-left direction at the protruding end (uppermost part) of the projection 11, two side surfaces 10b corresponding to the right and left surfaces of the projection 11, and two base surfaces 10c corresponding to the forming surfaces of the parts where the projection 11 is not formed. These surfaces serve as the so-called hat-shaped forming surface of the lower die 10.

[0022] The part of the lower die 10 where the upper surface 10a and the left side surface 10b meet is formed as a rounded outer corner 12. The part of the lower die 10 where the upper surface 10a and the right side surface 10b meet is formed as a rounded outer corner 13. The outer corners 12 and 13 serve as working parts when the lower die 10 and the upper die 20 press the workpiece W (see Fig. 3). It should be noted that the "working parts" of the dies (the lower die 10 and the upper die 20) are corners in the forming surfaces of the dies and are parts for bending the workpiece W when the dies press the workpiece W.

[0023] The upper die 20 corresponds to the lower die 10. The upper die 20 has a recess 21 that extends upward from the forming surface (the lower surface) of the upper die 20 in accordance with the configuration of the projection 11. The recess 21 is formed such that the forming surface of the upper die 20 is upwardly recessed. The recess 21 is continuous in the front-backward direction at the intermediate part (substantially the middle part) in the right-left direction of the forming surface of the upper die 20.

[0024] The upper die 20 has a bottom surface 20a extending in the right-left direction at the innermost part (the uppermost part) of the recess 21, two side surfaces 20b corresponding to the right and left surfaces of the recess 21, and two base surfaces 20c corresponding to the forming surfaces of the parts for which the recess 21 is not provided. These surfaces serve as a so-called hat-shaped forming surface of the upper die 20.

[0025] The part of the upper die 20 where the left side surface 20b and the left base surface 20c meet is formed as a rounded, outer corner 22. The part of the upper die 20 where the right side surface 20b and the right base surface 20c meet is formed as a rounded, outer corner 23. The outer corners 22 and 23 serve as working parts when the lower die 10 and the upper die 20 press the workpiece W (see Fig. 3).

[0026] The following describes the structures of the lower die 10 and the upper die 20 in detail.

[0027] The lower die 10 has recessed parts 14 and 15, which are recessed inwards starting from the forming surface of the lower die 10.

[0028] The trough part 14 is continuously formed in the front-back direction over the entire area of ​​the forming surface of the lower die 10 by inwardly recessing the part of the forming surface where the left side surface 10b and the left base surface 10c meet. In other words, the trough part 14 is provided at the part of the lower die 10 opposite the outer corner 22 of the upper die 20. The trough part 15 is continuously formed in the front-back direction over the entire area of ​​the forming surface of the lower die 10 by inwardly recessing the part of the forming surface where the right side surface 10b and the right base surface 10c meet. In other words, the trough part 15 is provided at the part of the lower die 10 opposite the outer corner 23 of the upper die 20.

[0029] A groove 16 is formed on the forming surface of the lower die 10.

[0030] As in Fig. 1 and Fig. As shown in Fig. 2, the groove 16 is a minute groove having a predetermined depth (dimension in the up-down direction) formed in the entire areas of the top surface 10a, the side surfaces 10b, and the bottom surfaces 10c. The groove 16 is composed of a plurality of grooves arranged parallel to each other at predetermined intervals and extending in a first direction, and a plurality of grooves arranged parallel to each other at predetermined intervals and extending in a second direction such that they intersect with the plurality of grooves extending in the first direction. Thus, the groove 16 is formed in a mesh shape.

[0031] As in Fig. 1, the lower die 10 has a water supply channel 17 and ventilation passages 18 and 19, wherein the water supply channel 17 and the ventilation passages 18 and 19 are formed within the lower die 10.

[0032] The water supply channel 17 is a channel through which cooling water flows to cool the heated workpiece W. The water supply channel 17 is drilled through the lower die 10 from the lower surface of the lower die 10 to the side surfaces 10b. The water supply channel 17 branches into a plurality of parts in the lower die 10, so that a plurality of openings are formed on the side surfaces 10b in the front-back direction (see Fig. 2). Note that each of the openings formed on the side surfaces 10b of the water supply channel 17 has an inner diameter such that the openings do not adversely affect the press processing of the workpiece W (that the press processing of the workpiece W is performed in a manner similar to conventional press processing).

[0033] The vent passages 18 and 19 are passages for discharging steam to the outside of the lower die 10, which steam is generated by the evaporation of the cooling water during quenching of the workpiece W. The vent passages 18 and 19 are formed from a surface of the lower die 10 other than the forming surface thereof toward a space between the lower die 10 and the workpiece W. Specifically, the vent passages 18 and 19 are drilled through the lower die 10 in the up-down direction from the lower surface of the lower die 10 toward trough portions 14 and 15, respectively.The ventilation passage 18 branches into a plurality of parts in the lower die 10 so that a plurality of openings are formed in the trough part 14 in the front-back direction, and the ventilation passage 19 branches into a plurality of parts in the lower die 10 so that a plurality of openings are formed in the trough part 15 in the front-back direction (see . Fig. 2).

[0034] The upper die 20 has recessed parts 24 and 25 which are recessed inwards starting from the forming surface of the upper die 20.

[0035] The trough part 24 is continuously formed in the front-back direction over the entire area of ​​the forming surface of the upper die 20 by inwardly recessing the part of the forming surface where the lower surface 20a and the left side surface 20b meet. In other words, the trough part 24 is provided at the part of the upper die 20 opposite the outer corner 12 of the lower die 10. The trough part 25 is continuously formed in the front-back direction over the entire area of ​​the forming surface of the upper die 20 by inwardly recessing the part of the forming surface where the lower surface 20a and the right side surface 20b meet. In other words, the trough part 25 is provided at the part of the upper die 20 opposite the outer corner 13 of the lower die 10.

[0036] A groove 26 is formed on the forming surface of the upper die 20.

[0037] The groove 26 is substantially similar in configuration to the groove 16 of the lower die 10. The groove 26 has a predetermined depth (dimension in the up-down direction) and is formed in a net or net-like manner in the entire areas of the lower surface 20a, the side surfaces 20b, and the base surfaces 20c.

[0038] The upper die 20 has a water supply channel 27 and ventilation passages 28 and 29, wherein the water supply channel 27 and the ventilation passages 28 and 29 are formed within the upper die 20.

[0039] The water supply channel 27 is a channel through which cooling water flows to cool the heated workpiece W. The water supply channel 27 is bored through the upper die 20 in the up-down direction from the upper surface of the upper die 20 to the lower surface 20a. Although not shown, the water supply channel 27 branches into a plurality of parts in the upper die 20, so that a plurality of openings are formed on the lower surface 20a in the front-back direction. Note that each of the openings of the water supply channel 27 formed on the lower surface 20a has an inner diameter such that the openings do not adversely affect the press processing of the workpiece W (so that the press processing of the workpiece W is performed in a manner similar to conventional press processing).

[0040] The vent passages 28 and 29 are passages for discharging steam to the outside of the upper die 20, which steam is generated by the evaporation of the cooling water during quenching of the workpiece W. The vent passages 28 and 29 are formed from a surface of the upper die 20 other than the forming surface thereof to a space between the upper die 20 and the workpiece W. The vent passage 28 is drilled through the upper die 20 in the right-left direction from the left surface of the upper die 20 to the trough parts 24. The vent passage 29 is drilled through the upper die 20 in the right-left direction from the right surface of the upper die 20 to the trough parts 25.Although not shown, the ventilation passage 28 in the upper die 20 branches into a plurality of parts so that a plurality of openings are formed in the trough part 24 in the front-back direction, and the ventilation passage 29 branches into a plurality of parts in the upper die 20 so that a plurality of openings are formed in the trough part 25 in the front-back direction.

[0041] The lower water supply device 30 and the lower suction device 40, which are connected to the lower die 10, and the upper water supply device 50 and the upper suction device 60, which are connected to the upper die 20, are described in detail below.

[0042] The lower water supply device 30 is a device, such as a pump, for supplying cooling water to the space between the lower die 10 and the workpiece W. The lower water supply device 30 pumps the cooling water at a predetermined pressure (for example, 10 atm) through the water supply channel 17 to the space between the lower die 10 and the workpiece W. Specifically, the lower water supply device 30 causes the cooling water stored in a predetermined housing to flow from the opening on the lower surface of the lower die 10 into the water supply channel 17 formed in the lower die 10 and to flow out from the openings on the side surfaces 10b. Therefore, the lower water supply device 30 and the water supply channel 17 serve as cooling water supplying means that supplies the cooling water to the space between the lower die 10 and the workpiece W.

[0043] The lower suction device 40 is a device, such as a pump, for exhausting steam generated by the evaporation of cooling water when the workpiece W is quenched. The lower suction device 40 is connected to the vents 18 and 19 opening on the lower surface of the lower die 10. The lower suction device 40 exhausts steam generated when the cooling water comes into contact with the lower surface of the high-temperature workpiece W through the vents 18 and 19 to discharge the steam to the outside of the lower die 10.

[0044] The upper water supply device 50 is a device, such as a pump, for supplying the cooling water to the space between the upper die 20 and the workpiece W. The upper water supply device 50 pumps the cooling water at a predetermined pressure (for example, 10 atm) through the water supply channel 27 to the space between the upper die 20 and the workpiece W. Specifically, the upper water supply device 50 causes the cooling water stored in a predetermined housing to flow from the opening on the upper surface of the upper die 20 into the water supply channel 27 formed in the upper die 20 and to flow out from the openings on the lower surface 20a. Therefore, the upper water supply device 50 and the water supply channel 27 serve as a cooling water supply device that supplies the cooling water to the space between the upper die 20 and the workpiece W.

[0045] The upper suction device 60 is a device, such as a pump, for exhausting steam generated by the evaporation of cooling water when the workpiece W is quenched. The upper suction device 60 is connected to the vent passage 28 opening on the left surface of the upper die 20. The upper suction device 60 exhausts steam generated when the cooling water comes into contact with the upper surface of the high-temperature workpiece W through the vent passages 28 and 29 to discharge the steam to the outside of the upper die 20.

[0046] The following is with reference to Fig. 3 and Fig. 4 describes in detail how the hot-pressing device 1 operates when performing the hot-press forming of the workpiece W.

[0047] As in Fig. 3, during the press processing of the workpiece W, when the upper die 20 moves close to the lower die 10 and arrives near the bottom dead center, the lower water supply device 30 supplies a predetermined amount of cooling water through the water supply channel 17 to the space between the lower die 10 and the workpiece W, and the upper water supply device 50 supplies a predetermined amount of cooling water through the water supply channel 27 to the space between the upper die 20 and the workpiece W. Note that black filled arrows in Fig. 3 indicate the directions in which the cooling water flows.

[0048] As in Fig. As shown in Figure 4, the press processing of the workpiece W ends when the upper die 20 reaches the bottom dead center, and the workpiece W is thereby formed into a so-called hat shape or hat-shaped shape. Then, the lower die 10 and the upper die 20 keep the forming surfaces thereof in contact with the lower and upper surfaces of the workpiece W for a predetermined time, thereby cooling the high-temperature workpiece W. Moreover, the cooling water supplied to the space between the lower die 10 and the workpiece W spreads through the groove 16 over the forming surface of the lower die 10, and the cooling water supplied to the space between the upper die 20 and the workpiece W spreads through the groove 26 over the forming surface of the upper die 20.Consequently, the forming surfaces of the lower die 10 and the upper die 20 come into contact with the surface of the workpiece W, and in addition, the cooling water comes into contact with the entire surface of the workpiece W, which makes it possible to cool the workpiece W appropriately.

[0049] As mentioned above, the groove 16 and the groove 26 are formed on the forming surface of the lower die 10 and the forming surface of the upper die 20, respectively. This makes it possible to cause the cooling water to be properly distributed over the forming surfaces of the lower die 10 and the upper die 20 through the groove 16 and the groove 26. In the present embodiment, both the groove 16 and the groove 26 are formed in a mesh shape, but the configurations of the groove 16 and the groove 26 are not limited as long as the cooling water is properly distributed over the forming surfaces of the lower die 10 and the upper die 20. For example, a plurality of grooves extending in the right-left direction may be formed at predetermined intervals in the front-back direction.

[0050] During the aforementioned quenching of the workpiece W, when the cooling water comes into contact with the surface of the high-temperature workpiece W, steam is generated as the cooling water evaporates. As the cooling water evaporates, its volume increases dramatically. As a result, steam generated between the forming surface of the lower die 10 and the lower surface of the workpiece W and steam generated between the forming surface of the upper die 20 and the upper surface of the workpiece W flow into the trough portions 14 and 15 formed on the forming surface of the lower die 10 and the trough portions 24 and 25 formed on the forming surface of the upper die 20, respectively.The steam which flowed into the trough parts 14 and 15 is discharged via the ventilation passages 18 and 19 through the lower suction device 40 to the outside of the lower die 10, and the steam which flowed into the trough parts 28 and 29 is discharged via the ventilation passages 28 and 29 through the upper suction device 60 to the outside of the upper die 20 (see white arrows in . Fig. 4). Note that the amount of cooling water supplied to the space between the lower die 10 and the workpiece W, and the space between the upper die 20 and the workpiece W is determined so that the cooling water completely evaporates. A suitable amount of cooling water can be determined because the amount of heat that the cooling water should absorb from the high-temperature workpiece W can be calculated in advance through simulation and the like. In the case where part of the cooling water remains as a liquid and the cooling water does not completely evaporate, the remaining cooling water is sucked and removed by the lower suction device 40 and the upper suction device 60.

[0051] Since the trough portions 14 and 15 and the trough portions 24 and 25 are formed at the forming surface of the lower die 10 and the forming surface of the upper die 20, respectively, the trough portions 14 and 15 and the trough portions 24 and 25 serve as spaces into which the steam generated between the lower die 10 and the workpiece W and the steam generated between the upper die 20 and the workpiece W flow. As a result, the high-temperature steam flows into the trough portions 14 and 15 and the trough portions 24 and 25 without remaining in the spaces between the surface of the workpiece W and the forming surfaces of the lower die 10 and the upper die 20. This makes it possible to effectively utilize the vaporization heat of the cooling water and cool the workpiece W at a sufficient cooling rate. In particular, in the present invention, the liquid cooling water is used to quench the workpiece W.As a result, even in cases where clearances are formed between the lower die 10 and the workpiece W and between the upper die 20 and the workpiece W, the clearances are filled with the aid of cooling water. This makes it possible to prevent the hardness of some parts of the workpiece from being less than a predetermined value.

[0052] As mentioned above, the trough portions 14 and 15 and the trough portions 24 and 25 are formed by removing the forming surfaces of the lower die 10 and the upper die 20 to press the workpiece W. In other words, no forming surfaces exist in the portions of the lower die 10 where the trough portions 14 and 15 are formed and in the portions of the upper die 20 where the trough portions 24 and 25 are formed. However, it is generally known that press processing is suitably performed even if the portions of the forming surface of one die that oppose the working portions of the other die do not exist.In the present embodiment, the trough portions 14 and 15 are provided at the parts of the lower die 10 opposite to the outer corners 22 and 23 of the upper die 20, and the trough portions 24 and 25 are provided at the parts of the upper die 20 opposite to the outer corners 12 and 13 of the lower die 10, which has no influence on the press processing of the workpiece W. Therefore, the trough portions 14 and 15 and the trough portions 24 and 25 are provided at parts that have no influence on the press processing of the workpiece W and are used as the spaces into which the steam flows. This makes it possible to effectively utilize the vaporization heat of the cooling water. Moreover, the pressures in the trough portions 14 and 15 and the pressures in the trough portions 24 and 25 are increased by the steam generated when the workpiece W is pressed (see ). Fig. 3). This makes it possible to apply pressure evenly to the parts of the workpiece W corresponding to the trough parts 14 and 15 and the trough parts 24 and 25 when the workpiece W is pressed.

[0053] Within the lower die 10, the ventilation passages 18 and 19 are formed from the surface of the lower die 10, which is different from the forming surface thereof, to the space between the lower die 10 and the workpiece W, and within the upper die 20, the ventilation passages 28 and 29 are formed from the surface of the upper die 20, which is different from the forming surface thereof, to the space between the upper die 20 and the workpiece W. As a result, the steam generated between the lower die 10 and the workpiece W and the steam generated between the upper die 20 and the workpiece W flow through the ventilation passages 18 and 19 and the ventilation passages 28 and 29 to the outside of the lower die 10 and the upper die 20. This makes it possible to appropriately cool the workpiece W using the heat of vaporization of the cooling water.Specifically, the vent passages 18 and 19 are formed such that the trough portions 14 and 15 communicate with the exterior of the lower die 10, and the vent passages 28 and 29 communicate with the exterior of the upper die 20. This makes it possible to effectively cause the steam that flowed into the trough portions 14 and 15 and the trough portions 24 and 25 to flow outside the lower die 10 and the upper die 20. This makes it possible to appropriately cool the workpiece W using the vaporization heat of the cooling water.

[0054] The lower suction device 40 and the upper suction device 60 are connected to the ventilation passages 18 and 19 and the ventilation passages 28 and 29, respectively. This makes it possible to cause the steam generated between the lower die 10 and the workpiece W and the steam generated between the upper die 20 and the workpiece W to flow outside the lower die 10 and the upper die 20 through the ventilation passages 18 and 19 and the ventilation passages 28 and 29. This makes it possible to appropriately cool the workpiece W using the vaporization heat of the cooling water.

[0055] In the present embodiment, the lower die 10 is provided with the ventilation passages 18 and 19 and the lower suction device 40, and the upper die 20 is provided with the ventilation passages 28 and 29 and the upper suction device 60. However, a configuration of the hot-pressing device 1 is not limited to this. For example, the lower die 10 may not be provided with the lower suction device 40 and only with the ventilation passages 18 and 19, and the upper die 20 may not be provided with the upper suction device 60 and only with the ventilation passages 28 and 29. Furthermore, the lower die 10 and the upper die 20 may not be provided with the ventilation passages 18, 19, 28, and 29 and the suction devices 40 and 60.

[0056] In the present embodiment, the vent passages 18 and 19 and the vent passages 28 and 29 are formed to open at the cavity portions 14 and 15 and the cavity portions 24 and 25, respectively. However, a configuration of the hot-pressing apparatus 1 is not limited to this. A flow of steam generated when the workpiece W is quenched differs depending on the configurations of the dies (the lower die 10 and the upper die 20) and the like. Thus, vent passages are formed to discharge the steam from locations between the surface of the workpiece W and the forming surfaces of the dies, where the steam flows, to the outside of the dies. In other words, the vent passages are formed at positions where the steam is difficult to remain in the spaces between the surface of the workpiece W and the forming surfaces of the dies.For example, since steam easily flows upward, the vents may be formed to open at the upper surface 10a located at the uppermost part of the lower die 10, so that the lower suction device 40 sucks the steam through the vents. Furthermore, the water supply channel 17 and the water supply channel 27 may be used as vents for discharging the steam, and the vents 18 and 19 and the vents 28 and 29 may be used as water supply channels for supplying cooling water. Note that the steam flow may be analyzed in advance through simulation and the like.

[0057] In the present embodiment, the cooling water is supplied to the spaces between the workpiece W and the dies when the upper die 20 arrives near the bottom dead center, that is, when the workpiece W is being pressed. However, the cooling water may be supplied to the spaces between the workpiece W and the dies after the upper die 20 arrives at the bottom dead center. In the present embodiment, the water supply channel 17 is formed such that the cooling water flows out from the openings on the side surfaces 10b, and the water supply channel 27 is formed such that the cooling water flows out from the openings on the bottom surface 20a. However, the positions at which the cooling water flowing into the spaces between the workpiece W and the dies is supplied are not limited. [Second embodiment]

[0058] The following is with reference to the Fig. 5 and Fig. 6, a hot-pressing device 100 is described as a second embodiment of a hot-pressing device according to the present invention. The hot-pressing device 100 performs the hot-press forming of the workpiece W. For the sake of simplicity, Fig. 5 defines an up-down direction as an up-down direction of the hot-pressing device 100, and a right-left direction in Fig. 5 is defined as a right-left direction of the hot-pressing device 100. In addition, the Fig. 5 is defined as the front side of the hot-pressing device 100 and the opposite side in Fig. 5 is defined as a rear side of the hot-pressing device 100, thereby defining a front-back direction of the hot-pressing device 100. Hereinafter, each of the parts common to the hot-pressing device 1 and the hot-pressing device 100 is denoted by the same reference numeral, and a description thereof will be omitted.

[0059] As in Fig. 5, the hot pressing apparatus 100 includes a lower die 110 and an upper die 120 whose forming surfaces are opposite to each other, the lower water supply device 30 connected to the lower die 110, and the upper water supply device 50 connected to the upper die 20.

[0060] The lower die 110 is substantially the same in configuration as the lower die 10 of the hot pressing apparatus 1. The lower die 110 differs from the lower die 10 in that the ventilation passages 18 and 19 are not provided and that a lower coolant spray line 170 is provided.

[0061] As in Fig. 6, the lower coolant spray pipe 170 is a pipe through which a coolant flows, and extends in the front-to-back direction. The lower coolant spray pipe 170 is provided at the tray portion 14 and arranged so that it does not come into contact with the workpiece W during press processing. On the outer peripheral surface of the lower coolant spray pipe 170, a plurality of minute through-holes connecting the inside and outside of the lower coolant spray pipe 170 are formed at predetermined intervals in the front-to-back direction. A predetermined device (not shown) causes the coolant supplied into the inside of the lower coolant spray pipe 170 to spray out from the plurality of through-holes in a mist-like manner. Thus, the lower coolant spray pipe 170 serves as a coolant supply device that supplies the coolant to the tray portion 14.In the present embodiment, liquid nitrogen is used as the coolant.

[0062] As in Fig. 5, the upper die 120 is substantially the same in configuration as the upper die 20 of the hot pressing apparatus 1. The upper die 120 differs from the upper die 20 in that the ventilation passages 28 and 29 are not provided and that an upper coolant injection line 180 is provided.

[0063] The upper coolant spray line 180 is a line through which the coolant flows and extends in the front-to-back direction. The upper coolant spray line 180 is provided at the trough portion 25 and arranged such that it does not come into contact with the workpiece W during press processing. Although not shown, a plurality of tiny through-holes are formed on the outer peripheral surface of the upper coolant spray line 180 at predetermined intervals in the front-to-back direction, connecting the inside and outside of the upper coolant spray line 180. A predetermined device (not shown) causes the coolant supplied into the interior of the upper coolant spray line 180 to spray out from the plurality of through-holes in a mist-like manner. Therefore, the upper coolant spray line 180 serves as a coolant supply device that supplies the coolant to the trough portion 25.

[0064] After the upper die 120 arrives near the bottom dead center and completes the press processing of the workpiece W, the lower water supply device 30 supplies a predetermined amount of cooling water to the space between the lower die 110 and the workpiece W through the water supply channel 17, and the upper water supply device 50 supplies a predetermined amount of cooling water to the space between the upper die 120 and the workpiece W through the water supply channel 27.

[0065] Then, the lower coolant spray line 170 sprays the coolant into the bowl portion 14 in a mist, and the upper coolant spray line 180 sprays the coolant into the bowl portion 25 in a mist. Since liquid nitrogen as the coolant sprayed from the lower coolant spray line 170 and the upper coolant spray line 180 turns into a mist, the liquid nitrogen in the bowl portion 14 and the bowl portion 25 immediately evaporates and drastically increases in volume. As a result, the pressure in the bowl portion 14 and the bowl portion 25 increases. Consequently, the cooling water supplied to the space between the lower die 110 and the workpiece W flows in such a way that it moves away from the trough part 14, and the cooling water supplied to the space between the upper die 20 and the workpiece W flows in such a way that it moves away from the trough part 25 (see black filled arrows in Fig. 5).

[0066] As mentioned above, the gaseous coolant filling the cavity portion 14 and the cavity portion 25 serves as a pump for causing the cooling water to flow. This makes it possible to properly distribute the cooling water over the forming surfaces of the lower die 110 and the upper die 120. Moreover, the coolant cools the surrounding cooling water and the like, thus making it possible to quickly cool the workpiece W. In the present embodiment, the lower coolant injection line 170 is provided at the cavity portion 14, and the upper coolant injection line 180 is provided at the cavity portion 25. However, a configuration of the hot-pressing apparatus 100 is not limited to this as long as the cooling water flows properly.In other words, a lower coolant injection line may be provided at least at one of the bowl parts 14 and 15, and an upper coolant injection line may be provided at least at one of the bowl parts 24 and 25. In the present embodiment, the lower coolant injection line 170 is used as the coolant supply means that supplies the coolant to the bowl part 14, and the upper coolant injection line 180 is used as the coolant supply means that supplies the coolant to the bowl part 25. However, other coolant supply means may be used. In the present embodiment, the lower die 110 and the upper die 120 are not provided with the vent passages 18 and 19 and the vent passages 28 and 29, respectively. However, the lower die 110 and the upper die 120 may be provided with the ventilation openings 18 and 19 and the ventilation openings 28 and 29, respectively.In addition, the lower suction device 40 and the upper suction device 60 can be connected to the ventilation passages 18 and 19 and the ventilation passages 28 and 29, respectively.

[0067] In each embodiment mentioned above, the lower die is provided with the trough portions 14 and 25, and the upper die is provided with the trough portions 24 and 25. However, the configurations of the lower and upper dies are not limited thereto, and a trough portion may be provided in at least one of the lower and upper dies. In the case where the trough portion is provided in only one of the lower and upper dies, the cooling water cannot be supplied to the space between the workpiece W and the other die (die not provided with a trough portion). In each embodiment mentioned above, the dies consist of the lower die with a projection and the upper die with a recess. However, the dies may consist of the lower die with a recess and the upper die with a projection.In each of the above-mentioned embodiments, the dies have configurations for forming the workpiece W into the hat-shaped form, but the configurations thereof are not limited thereto. The present invention can be applied to a hot-pressing device having lower and upper dies with other configurations. Industrial applicability

[0068] The present invention is applied to a hot pressing apparatus which simultaneously presses and cools a heated workpiece. List of reference symbols 1 hot pressing device 10 Lower die 11 lead 12, 13 outer corner (working part) 14, 15 Trough part 16 grooves 17 Water supply channel (cooling water supply device) 18, 19 Ventilation opening 20 upper die 21 recess 22, 23 outer corner (working part) 24, 25 Trough part 26 grooves 27 Water supply channel (cooling water supply device) 28, 29 Ventilation opening 30 lower water supply device (cooling water supply device) 40 lower suction device (suction device) 50 upper water supply device (cooling water supply device) 60 upper suction device (suction device) 100 hot pressing device 110 Lower die 120 upper die 170 lower coolant spray newspaper (coolant supply device) 180 upper coolant spray newspaper (coolant supply device)

Claims

[1] A hot-pressing device (1) comprising a lower die (10) having a lower forming surface and an upper die (20) having an upper forming surface opposite the lower forming surface, which causes the lower die (10) and the upper die (20) to press a heated workpiece (W) arranged therebetween and that the forming surfaces thereof are simultaneously held in contact with a surface of the workpiece (W) to cool the workpiece (W), the improvement comprising: a trough part (14, 15, 24, 25) which is recessed inwardly from the forming surface of the lower die (10) and / or the upper die (20), and which is formed in a part of the lower die (10) opposite an outer corner (22, 23) of the upper die (20) acting as a working part for bending the workpiece (W), and / or a part of the upper die (20) opposite an outer corner (12, 13) of the lower die (10) acting as the working part; and a cooling water supply device (17, 27, 30, 50) which supplies cooling water for cooling the workpiece (W) to a space between the workpiece (W) and the lower die (10) and / or the upper die (20) where the trough part (14, 15, 24, 25) is formed, wherein the lower die (10) and / or the upper die (20) has, at the location where the trough part (14, 15, 24, 25) is formed, a ventilation passage (18, 19, 28, 29) through which steam flows, which is generated when the cooling water comes into contact with the workpiece (W), and the ventilation passage (18, 19, 28, 29) is formed within the lower die (10) and / or the upper die (20) from a surface thereof other than the forming surface towards the space between the workpiece (W) and the lower die (10) and / or the upper die (20). [2] Hot pressing device (1) according to claim 1, wherein the ventilation passage (18, 19, 28, 29) is formed from a surface of the lower die (10) and / or the upper die (20) other than the forming surface towards the trough part (14, 15, 24, 25). [3] Hot pressing device (1) according to claim 1 or 2, further comprising: a suction device (40, 60) which sucks off the steam flowing through the ventilation passage (18, 19, 28, 29), wherein the suction device (40, 60) is connected to the ventilation passage (18, 19, 28, 29). [4] Hot pressing device (1) according to one of claims 1 to 3, further comprising: a coolant supply device (170, 180) which supplies a coolant to the trough part (14, 15, 24, 25), wherein the coolant supply device (170, 180) is arranged in the trough part (14, 15, 24, 25).

Images