JP6417138B2 - Molding equipment - Google Patents

Description

  The present invention relates to a molding apparatus.

  2. Description of the Related Art Conventionally, a molding apparatus that molds a heated metal material by closing the mold with a mold is known. For example, the molding apparatus disclosed in Patent Document 1 includes a mold, an energizing terminal that energizes and heats the metal pipe material, and a gas supply unit that supplies gas into the metal pipe material. In this molding apparatus, the metal pipe material heated by the energizing terminal is placed in the mold, and the metal pipe material is expanded by supplying gas from the gas supply portion to the metal pipe material in a state where the mold is closed. The material is formed into a shape corresponding to the shape of the mold.

JP 2003-154415 A

  In the forming apparatus of Patent Document 1, the metal pipe material is heated in the atmosphere to a temperature range where rapid quenching can be performed. In this case, the surface of the metal pipe material is oxidized, and an oxide layer is generated on the surface. If this oxide layer remains on the surface of the molded product, the appearance and material strength of the molded product may be affected. Therefore, it has been desired to improve the quality of the molded product.

  This invention is made | formed in view of the said situation, and it aims at providing the shaping | molding apparatus which can improve quality.

  A molding apparatus according to the present invention is a molding apparatus that molds a heated metal material by closing a mold, and a gas supply unit that blows gas onto the metal material and removes an oxide layer adhering to the surface of the metal material And a control unit that controls the gas supply unit, and the control unit controls the gas supply unit so as to blow gas onto the metal material after the mold is opened.

  In this molding apparatus, even if an oxide layer is generated on the surface of the metal material during the molding process, the control unit controls the gas supply unit to blow gas onto the metal material after the mold is opened. Thereby, it is possible to suppress the oxide layer from remaining on the surface of the molded product by removing the oxide layer attached to the surface of the metal material. Thereby, it can suppress that the external appearance and material strength of a molded product are influenced, and it becomes possible to improve the quality of a molded product.

  In the molding apparatus according to the present invention, the metal material may be a metal pipe material, and the gas supply unit may spray gas on both the inner surface and the outer surface of the metal pipe material. According to this shaping | molding apparatus, it becomes possible to remove the oxide layer adhering to both the inner surface and outer surface of a metal pipe, and it becomes possible to improve the quality of a molded product effectively.

  Further, in the molding apparatus according to the present invention, the control unit may control the gas supply unit so as to start blowing the gas to the metal material at a time point when the temperature of the metal material is higher than the martensite transformation end temperature. . In the molding apparatus according to the present invention, there is a case where the metal material is molded by a mold and then quenched by cooling the metal material. The strength of the metal material after quenching varies depending on the cooling rate in the region below the martensitic transformation start temperature. Moreover, the cooling rate by blowing the gas from the gas supply unit is slower than the cooling rate by other cooling means, for example, the cooling rate by contact with the mold. Therefore, according to this molding apparatus, at the time of quenching, when the temperature of the metal material is higher than the martensite transformation end temperature, gas blowing by the gas supply unit is started, and the cooling rate is delayed, thereby forming the molded product. It is possible to perform quenching suitable for the required characteristics. That is, the gas supply unit can be used not only for removing the oxide layer but also for adjusting the cooling rate.

  Moreover, in the shaping | molding apparatus which concerns on this invention, a control part may control a gas supply part so that the blowing of the gas to a metal material may be started at the time of the temperature of a metal material being below a martensitic transformation completion temperature. According to this forming apparatus, since the gas is sprayed after the temperature of the metal material is lowered, the oxide layer is easily removed from the metal material. That is, there is a possibility that the oxide layer is difficult to peel off from the surface of the metal material when the temperature of the metal material is high. In this molding apparatus, spraying is performed after the temperature of the metal material falls below the martensite transformation end temperature. Therefore, the oxide layer is easily removed from the metal material. For this reason, it becomes possible to easily remove the oxide layer from the metal material.

  In the molding apparatus according to the present invention, when the gas supply unit sprays gas onto the metal material, the mold may be in a state in which the cavity is closed in a cross section viewed from the gas blowing direction by the gas supply unit. According to this molding apparatus, when the gas is sprayed from the gas supply unit, it is possible to suppress the sprayed gas and the oxide layer removed by the gas from being ejected to the side. It can be removed.

  The molding apparatus according to the present invention further includes an abutting portion that abuts on the metal material, and the control unit controls the gas supply unit so as to blow gas onto the metal material after the mold is opened, and The contact portion may be controlled so as to contact the metal material. According to this molding apparatus, the oxide layer can be peeled off or easily peeled off from the surface of the metal material by applying vibration or impact to the metal material by the contact portion, so that the oxide layer can be effectively removed. Is possible.

  ADVANTAGE OF THE INVENTION According to this invention, the shaping | molding apparatus which can improve the quality of a molded article can be provided.

It is a schematic block diagram of the shaping | molding apparatus which concerns on embodiment of this invention. It is sectional drawing along the II-II line | wire shown in FIG. 1, Comprising: It is a schematic sectional drawing of a blow molding die. It is a figure which shows the manufacturing process by a shaping | molding apparatus, Comprising: (a) is a figure which shows the state by which the metal pipe material was set in the metal mold | die, (b) is a figure which shows the state by which the metal pipe material was hold | maintained at the electrode. is there. It is a figure which shows the blow molding process by a shaping | molding apparatus, and a subsequent flow. It is an enlarged view of the periphery of the electrode, (a) is a diagram showing a state in which the electrode holds the metal pipe material, (b) is a diagram showing a state in which the blow mechanism is in contact with the electrode, (c) FIG. 3 is a front view of an electrode. It is a figure which shows a mode that the oxide layer removal process is performed. It is a schematic sectional drawing of the blow molding die at the time of an oxide layer removal. It is a figure which shows the oxide layer removal process which concerns on a modification. It is a figure which shows the oxide layer removal process which concerns on a modification. It is a figure which shows the oxide layer removal process which concerns on a modification. It is a graph which shows the relationship between time at the time of quenching, and temperature.

<Configuration of molding equipment>
As shown in FIG. 1, a molding apparatus 10 for molding a metal pipe includes a blow molding die (die) 13 including an upper die 12 and a lower die 11, and at least one of the upper die 12 and the lower die 11. A slide 82 to be moved, a drive unit 81 that generates a driving force for moving the slide 82, a pipe holding mechanism 30 that horizontally holds the metal pipe material 14 between the upper mold 12 and the lower mold 11, and A heating mechanism (heating unit) 50 for energizing and heating the metal pipe material 14 held by the pipe holding mechanism 30, and a blow mechanism (gas supply unit) 60 for blowing high-pressure gas into the heated metal pipe material 14. , Drive unit 81, pipe holding mechanism 30, operation of blow molding die 13, control unit 70 for controlling heating mechanism 50 and blow mechanism 60, and water circulation mechanism 72 for forcibly cooling blow molding die 13. It is configured to include a. As will be described later, the blow mechanism 60 also functions as a gas supply unit that blows gas onto the molded metal pipe 80 and removes an oxide layer attached to the surface of the metal pipe 80. The blow mechanism 60 can also be used to cool the formed metal pipe 80, as will be described later. The control unit 70 closes the blow molding die 13 when the metal pipe material 14 is heated to the quenching temperature (AC3 transformation point temperature or higher) and injects high-pressure gas into the heated metal pipe material 14. Take control. In the following description, the formed pipe is referred to as a metal pipe 80 (see FIG. 2B), and the pipe in the middle of completion is referred to as a metal pipe material 14.

  The lower mold 11 is fixed to a large base 15. Moreover, the lower mold | type 11 is comprised with the big steel block, and is provided with the cavity (recessed part) 16 on the upper surface. Further, an electrode storage space 11a is provided in the vicinity of the left and right ends (left and right ends in FIG. 1) of the lower mold 11, and a first electrode 17 configured to be movable back and forth by an actuator (not shown) in the space 11a. A second electrode 18 is provided. On the upper surfaces of the first and second electrodes 17 and 18, semicircular arc-shaped grooves 17a and 18a corresponding to the lower outer peripheral surface of the metal pipe material 14 are formed (see FIG. 5C). It can be placed so that the metal pipe material 14 fits in the concave grooves 17a and 18a. In addition, tapered front surfaces 17b and 18b whose front surfaces (surfaces in the outer side of the mold) of the first and second electrodes 17 and 18 are recessed toward the concave grooves 17a and 18a in a tapered manner are formed. Yes. A cooling water passage 19 is formed in the lower mold 11 and includes a thermocouple 21 inserted from below at a substantially central position. The thermocouple 21 is supported by a spring 22 so as to be movable up and down.

  The pair of first and second electrodes 17 and 18 located on the lower mold 11 side also serves as a pipe holding mechanism 30 so that the metal pipe material 14 can be raised and lowered between the upper mold 12 and the lower mold 11. Can be supported horizontally. The thermocouple 21 is merely an example of a temperature measuring means, and may be a non-contact temperature sensor such as a radiation thermometer or an optical thermometer. If a correlation between the energization time and the temperature can be obtained, the temperature measuring means can be omitted and configured sufficiently.

  The upper mold 12 is a large steel block having a cavity (concave portion) 24 on the lower surface and a cooling water passage 25 built therein. The upper mold 12 has an upper end fixed to the slide 82. The slide 82 to which the upper mold 12 is fixed is suspended by the pressure cylinder 26 and guided by the guide cylinder 27 so as not to shake. The drive unit 81 according to the present embodiment includes a servo motor 83 that generates a drive force for moving the slide 82. The drive unit 81 is configured by a fluid supply unit that supplies a fluid that drives the pressurizing cylinder 26 (operating oil when a hydraulic cylinder is used as the pressurizing cylinder 26) to the pressurizing cylinder 26. The control unit 70 can control the movement of the slide 82 by controlling the amount of fluid supplied to the pressurizing cylinder 26 by controlling the servo motor 83 of the driving unit 81. Note that the drive unit 81 is not limited to the one that applies a driving force to the slide 82 via the pressure cylinder 26 as described above. For example, the servo motor 83 is generated by mechanically connecting the drive unit to the slide 82. The driving force to be applied may be applied to the slide 82 directly or indirectly. In the present embodiment, only the upper mold 12 moves, but the lower mold 11 may move in addition to the upper mold 12 or instead of the upper mold 12. In the present embodiment, the drive unit 81 may not include the servo motor 83.

  Further, in the electrode storage space 12a provided in the vicinity of the left and right ends (left and right ends in FIG. 1) of the upper mold 12, as in the lower mold 11, the first is configured so that it can be moved up and down by an actuator (not shown). An electrode 17 and a second electrode 18 are provided. The lower surfaces of the first and second electrodes 17 and 18 are formed with semicircular arc-shaped grooves 17a and 18a corresponding to the upper outer peripheral surface of the metal pipe material 14 (see FIG. 5C). The metal pipe material 14 can be fitted into the concave grooves 17a and 18a. In addition, tapered front surfaces 17b and 18b whose front surfaces (surfaces in the outer side of the mold) of the first and second electrodes 17 and 18 are recessed toward the concave grooves 17a and 18a in a tapered manner are formed. Yes. In other words, when the metal pipe material 14 is sandwiched from above and below by the pair of upper and lower first and second electrodes 17 and 18, the outer periphery of the metal pipe material 14 can be surrounded so as to be in close contact with the entire circumference. Has been.

  FIG. 2 shows a schematic cross section of the blow molding die 13. This is a cross-sectional view of the blow molding die 13 taken along the line II-II in FIG. 1, and shows the state of the die position during blow molding. As shown in FIG. 2, when the reference line S is the upper surface of the lower mold 11 and the lower surface of the upper mold 12, a rectangular recess 11 b is formed on the upper surface of the lower mold 11. A rectangular recess 12 b is formed at a position facing the recess 11 b of the lower mold 11. Further, on the upper surface of the lower mold 11, a rectangular convex portion 11c is formed on one side (left side in FIG. 2) of the concave portion 11b, and the other side (right side in FIG. 2) of the concave portion 11b. ) Is formed with a rectangular recess 11d. Further, a rectangular concave portion 12d is formed on the lower surface of the upper mold 12 at a position corresponding to the convex portion 11c of the lower mold 11, and a rectangular convex portion 12c is formed at a position corresponding to the concave portion 11d. Yes. When the blow mold 13 is closed, the concave portion 11b of the lower mold 11 and the concave portion 12b of the upper mold 12 are combined to form the main cavity portion MC that is a rectangular space. At this time, the convex part 11c of the lower mold 11 and the concave part 12d of the upper mold 12 are fitted, and the concave part 11d of the lower mold 11 and the convex part 12c of the upper mold 12 are fitted. As shown in FIG. 2A, the metal pipe material 14 disposed in the main cavity portion MC expands to come into contact with the inner wall surface of the main cavity portion MC as shown in FIG. The main cavity portion MC is formed into a shape (here, a rectangular cross section).

  The heating mechanism 50 includes a power source 51, a lead wire 52 extending from the power source 51 and connected to the first electrode 17 and the second electrode 18, and a switch 53 interposed in the lead wire 52.

  The blow mechanism 60 includes a high-pressure gas source 61, an accumulator 62 that stores the high-pressure gas supplied from the high-pressure gas source 61, a first tube 63 that extends from the accumulator 62 to the cylinder unit 42, and the first tube 63. A pressure control valve 64 and a switching valve 65 interposed between the second tube 67 and the second tube 67 extending from the accumulator 62 to the gas passage 46 formed in the seal member 44. And an on / off valve 68 and a check valve 69. Note that a tapered surface 45 is formed so that the tip of the seal member 44 is tapered, and the sealing member 44 has a shape that can be fitted and brought into contact with the tapered concave surfaces 17b and 18b of the first and second electrodes. (See FIG. 5). The seal member 44 is connected to the cylinder unit 42 via the cylinder rod 43, and can advance and retract in accordance with the operation of the cylinder unit 42. The cylinder unit 42 is mounted and fixed on the base 15 via the block 41.

  The pressure control valve 64 serves to supply the cylinder unit 42 with a high-pressure gas having an operating pressure adapted to the pressing force required from the seal member 44 side. The check valve 69 serves to prevent the high pressure gas from flowing back in the second tube 67. The control unit 70 acquires temperature information from the thermocouple 21 by transmitting information from (A) to (A), and controls the pressurizing cylinder 26, the switch 53, the switching valve 65, the on / off valve 68, and the like. .

  The water circulation mechanism 72 includes a water tank 73 for storing water, a water pump 74 that pumps up the water stored in the water tank 73, pressurizes the water, and sends it to the cooling water passage 19 of the lower mold 11 and the cooling water passage 25 of the upper mold 12; It consists of a pipe 75. Although omitted, a cooling tower for lowering the water temperature and a filter for purifying water may be interposed in the pipe 75.

<Operation of molding equipment>
Next, the operation of the molding apparatus 10 will be described. FIG. 3 shows a process from a pipe feeding process in which a metal pipe material 14 as a material is fed to an energization heating process in which the metal pipe material 14 is energized and heated. As shown in FIG. 3 (a), a hardenable metal pipe material 14 of a steel type is prepared, and this metal pipe material 14 is provided on the lower mold 11 side by a robot arm or the like (not shown). Place on the electrodes 17, 18. Since the grooves 17a and 18a are formed in the first and second electrodes 17 and 18, the metal pipe material 14 is positioned by the grooves 17a and 18a. Next, the control unit 70 (see FIG. 1) controls the pipe holding mechanism 30 to cause the pipe holding mechanism 30 to hold the metal pipe material 14. Specifically, as shown in FIG. 3B, an actuator (not shown) that allows the electrodes 17 and 18 to move forward and backward is actuated to bring the first and second electrodes 17 and 18 positioned above and below to approach each other.・ Contact. By this contact, both end portions of the metal pipe material 14 are sandwiched by the first and second electrodes 17 and 18 from above and below. Further, this clamping is held in such a manner that the metal pipe material 14 is in close contact with each other due to the presence of the concave grooves 17 a and 18 a formed in the first and second electrodes 17 and 18. However, the configuration is not limited to the configuration in which the metal pipe material 14 is in close contact with the entire circumference, and the first and second electrodes 17 and 18 may be in contact with a part of the metal pipe material 14 in the circumferential direction. .

  Subsequently, the control unit 70 heats the metal pipe material 14 by controlling the heating mechanism 50. Specifically, the control unit 70 turns on the switch 53 of the heating mechanism 50. If it does so, electric power will be supplied to the metal pipe material 14 from the power supply 51, and metal pipe material 14 itself heat | fever-generates with the resistance which exists in the metal pipe material 14 (Joule heat). At this time, the measured value of the thermocouple 21 is constantly monitored, and energization is controlled based on the result.

  FIG. 4 shows the processing content after blow molding and blow molding. Specifically, as shown in FIG. 4A, the blow molding die 13 is closed with respect to the heated metal pipe material 14, and the metal pipe material 14 is placed in the cavity of the blow molding die 13. Seal the arrangement. Thereafter, the cylinder unit 42 is operated to seal both ends of the metal pipe material 14 with the seal member 44 which is a part of the blow mechanism 60 (see also FIG. 5). In this seal, the seal member 44 does not directly contact and seal against both end faces of the metal pipe material 14, but indirectly through the tapered concave surfaces 17b and 18b formed on the first and second electrodes 17 and 18. Done. As a result, the sealing performance can be improved because the sealing can be performed over a wide area, the wear of the sealing member due to the repeated sealing operation can be prevented, and further, the crushing of both end faces of the metal pipe material 14 can be effectively prevented. ing. After the sealing is completed, high-pressure gas is blown into the metal pipe material 14 from the gas passage 46, and the metal pipe material 14 softened by heating is deformed so as to follow the shape of the cavity. At this time, the high-pressure gas blown into the metal pipe material is exhausted from the exhaust port 47.

  The metal pipe material 14 is softened by being heated to a high temperature (around 950 ° C.), and can be blow-molded at a relatively low pressure. Specifically, when compressed air at normal temperature (25 ° C.) at 4 MPa is adopted as the high-pressure gas, the compressed air is eventually heated to around 950 ° C. in the sealed metal pipe material 14. The compressed air expands thermally and reaches about 16-17 MPa based on Boyle-Charles' law. That is, the metal pipe material 14 at 950 ° C. can be easily blow-molded.

  The outer peripheral surface of the metal pipe material 14 blown and expanded contacts the cavity 16 of the lower mold 11 and is rapidly cooled, and simultaneously contacts the cavity 24 of the upper mold 12 to rapidly cool (the upper mold 12 and the lower mold). 11 has a large heat capacity and is controlled at a low temperature, so that when the metal pipe material 14 comes into contact, the heat of the pipe surface is taken away to the mold side at once. Such a cooling method is called mold contact cooling or mold cooling. Thereafter, when the mold is opened, the finished metal pipe 80 is completed.

<Oxide layer removal process>
By the way, when the metal pipe material 14 is heated to a high temperature around 950 ° C. in the atmosphere as described above, the surface of the metal pipe material 14 is oxidized, and an oxide layer is generated on the surface. If this oxide layer remains on the surface of the metal pipe 80 which is a molded product, the appearance and material strength may be affected. For example, when an oxide layer remains on the surface of the metal pipe 80, the paintability and the like are affected. In addition, when an oxide layer remains on the surface of the metal pipe 80, there is a possibility of causing poor welding. Therefore, in the molding apparatus 10 of the present embodiment, after the mold is opened, the blow mechanism 60 is used to blow gas onto the molded metal pipe 80 to remove the oxide layer adhering to the surface of the metal pipe 80.

  An example of the oxide layer removing step will be described with reference to FIG. In the shaping | molding apparatus 10 shown in FIG. 6, the blow mechanism 60 is used as a gas supply part which blows gas to the metal pipe 80. FIG. In the example shown in FIG. 6, the control unit 70 controls the operation of the blow molding die 13 so that the blow molding die 13 and the metal pipe 80 are kept in contact with each other for a predetermined time after the molding is completed. By doing so, the metal pipe 80 is cooled by the blow molding die 13. Then, after the metal pipe 80 is cooled by the blow molding die 13, the oxide layer is removed by the blow mechanism 60.

  As shown in FIG. 6 (a), immediately after the completion of molding by the blow molding die 13, the control unit 70 controls the operation of the blow molding die 13 to flow the cooling water into the cooling water passage 25, and The state where the upper die 12 and the lower die 11 are closed is maintained, and the state where the blow molding die 13 and the metal pipe 80 are in contact with each other is maintained for a predetermined time. Thereby, conduction heat transfer from the metal pipe 80 to the blow molding die 13 is performed, and the metal pipe 80 is cooled by the blow molding die 13.

  Next, as shown in FIG. 6 (b), after the cooling of the metal pipe 80 by the blow molding die 13, the control unit 70 opens the blow molding die 13 so as to open the blow molding die 13. Control the operation. In addition, the control unit 70 controls the blow mechanism 60 to separate the seal member 44 from both ends of the metal pipe 80. At this time, as shown in FIG. 6C, the control unit 70 forms a gap GP between the surface of the recess 11b of the lower mold 11 and the outer surface of the metal pipe 80, and the recess 12b of the upper mold 12. The blow mold 13 is controlled to open so that a gap GP is formed between the surface of the metal pipe 80 and the outer surface of the metal pipe 80. The control unit 70 controls the ejector pin 91 to open the blow mold in a state where a gap is provided between the surface of the blow mold 13 and the outer surface of the metal pipe 80. 13 holds the metal pipe 80.

  In this state, the control unit 70 controls the blow mechanism 60 to blow high-pressure gas as the blowing gas BA from the tip of the seal member 44 toward the end of the metal pipe 80. In this example, the control unit 70 controls the blow mechanism 60 so as to blow the blowing gas BA from only one side in the longitudinal direction of the blow molding die 13. Thereby, the blowing gas BA flows into the inside of the metal pipe 80 and the gap GP, and is blown to the inner surface and the outer surface of the metal pipe 80. When the blowing gas BA is blown, the oxide layer attached to the inner surface and the outer surface of the metal pipe 80 is peeled off and blown off, and is blown together with the blowing gas BA from the other end side in the longitudinal direction of the blow mold 13. In this way, the oxide layer attached to the surface of the metal pipe 80 is removed. In the above example, the high pressure gas is blown from the blow mechanism 60 as in the case of molding. However, normal pressure gas may be blown from the blow mechanism 60 instead of the high pressure gas.

  FIG. 7 shows a schematic cross section of the blow mold 13 in the mold open state shown in FIG. As shown in FIG. 7, in the molding apparatus 10 of the present embodiment, the blow molding die 13 causes the blowing mechanism BA to spray the blowing gas BA when the blowing mechanism 60 sprays the blowing gas BA onto the metal pipe 80 (FIG. 7). 7 is formed so that the main cavity portion MC is in a closed state in a cross section viewed from a direction perpendicular to the paper surface in FIG. That is, the protruding heights of the protrusion 11c of the lower mold 11 and the protrusion 12c of the upper mold 12 are set to be larger than the gap GP formed between the surface of the blow molding die 13 and the outer surface of the metal pipe 80. Thus, the main cavity portion MC is closed in the cross section when the mold is opened. Thereby, when spraying gas BA is sprayed, since the sprayed gas BA and the oxide layer removed by the spraying gas BA do not spout to the side, the oxide layer is effectively removed. It becomes possible. In the present embodiment, the example in which the protrusions (11c, 12c) are formed on each of the lower mold 11 and the upper mold 12 has been described. However, the main cavity MC communicates with the outside in the cross section when the mold is opened. The shape of the blow molding die 13 is not limited to this. For example, the structure by which two convex parts were formed in the lower mold | type 11 side may be sufficient.

  Furthermore, in parallel with the removal of the oxide layer by the blowing gas BA, vibration or impact may be applied to the metal pipe 80 by bringing the pin 91 of the ejector into contact therewith. That is, the ejector pin 91 may be used as a contact portion that contacts the metal pipe 80. In this case, the control unit 70 controls the blow mechanism 60 so that the blowing gas BA is blown onto the metal pipe 80 after the mold is opened, and also controls the pin 91 of the ejector so as to contact the metal pipe 80. Thus, the oxide layer can be peeled off from the surface of the metal pipe 80 by applying vibration or impact, or can be easily peeled off, so that the oxide layer can be effectively removed. At this time, since the oxide layer can be peeled even with a relatively small vibration or impact, the pin 91 is brought into contact with the molded product so as not to be damaged. Further, the timing for applying the vibration or impact by bringing the pin 91 into contact can be any timing after the mold is opened. For example, even when the application of the vibration or impact is started before the blowing gas BA is started to be blown. Alternatively, the application of vibration or impact may be started after the blowing gas BA is started to be blown. Alternatively, vibration or impact may be applied for a predetermined time before the blowing gas BA is blown.

  In addition to the example shown in FIG. 6, the oxide layer may be removed as follows, for example. For example, the blowing gas BA may be sprayed only on the inner surface of the metal pipe 80 by supplying the blowing gas BA as shown in FIG. In this case, as shown in FIG. 8A, the blowing gas BA may be supplied from one side of the metal pipe 80 and discharged together with the oxide layer from the same side. Further, as shown in FIG. 8B, the blowing gas BA may be supplied from both sides of the metal pipe 80 and discharged from both sides. Or it is good also as a structure which provides the supply port and discharge port of blowing gas BA in the same side by setting it as a double tube structure. Moreover, as shown in FIG.8 (c), the blowing gas BA may be supplied from the one side of the metal pipe 80, and you may discharge | emit from the opposite side. In the example illustrated in FIG. 6, the example in which the blow mechanism 60 is used as the gas supply unit for blowing the blowing gas BA has been described. However, unlike the example illustrated in FIG. 8, the blow mechanism 60 is different. It is good also as a structure provided with a mechanism as a gas supply part. However, if the blow mechanism 60 for expanding the metal pipe 80 is used as the gas supply unit, the molding apparatus 10 can be made compact.

  Further, as shown in FIGS. 9A and 9B, when the blowing gas BA is supplied to both the inner surface and the outer surface of the metal pipe 80, the outer surface of the metal pipe 80, the surface of the blow mold, Supply paths 93 for supplying the blowing gas BA to the gaps between the metal pipes 80 may be provided on both sides. In addition, as shown to Fig.9 (a), the flow direction of the blowing gas BA sprayed on the inner surface of the metal pipe 80 and the flow direction of the blowing gas BA sprayed on an outer surface may be reverse. Further, as shown in FIGS. 9C and 9D, a structure in which the oxide layer is blown off on the inner surface and the outer surface of the metal pipe 80 may be employed. As shown in FIGS. 9C and 9D, the supply path 93 is communicated with a gap outside the metal pipe 80 at the end of the metal pipe 80 on the side where the blowing gas BA is supplied. On the other hand, at the end on the discharge side, the supply path 93 is released so that the blowing gas BA that has passed through the gap outside the metal pipe 80 is removed as it is. In this state, the blowing gas BA is supplied from one end of the metal pipe 80 to the inside and the outside of the metal pipe 80, and is discharged together with the oxide layer from the other end. At this time, in order to prevent the oxide layer from scattering, an oxide layer receiving portion 94 constituted by a metal net or the like may be provided at the end on the discharge side. In addition, when the oxide layer cannot be discharged by spraying from one direction of the metal pipe 80, switching the supply direction is repeated a plurality of times by switching the states of FIG. 9 (c) and FIG. 9 (d). Also good.

  Further, as shown in FIG. 10, a supply path 97 for flowing the blowing gas BA may be provided inside the blow molding die 13. The supply path 97 is provided substantially at the center in the length direction of the lower mold 11 and the upper mold 12. With this configuration, the blowing gas BA is supplied to the gap GP outside the metal pipe 80 via the supply path 97 inside the blow molding die 13, and the blowing gas BA is discharged together with the oxide layer from both ends of the metal pipe 80. The For this reason, in the example of FIG. 10, the oxide layer receiving part 94 is provided in both ends. At the time of molding, the supply path 97 is sealed with a pin 96, and a molding surface is secured by the tip surface of the pin 96.

<Cooling of metal pipes>
The blowing gas BA from the blow mechanism 60 may be used not only for removing the oxide layer but also for cooling the metal pipe 80 after forming. In this case, after the molding by the blow molding die 13 is completed, the control unit 70 controls the operation of the blow molding die 13 so as to open the blow molding die 13, and then blows the blowing gas BA into the metal pipe 80. By controlling the blow mechanism 60 so as to spray the metal pipe 80, the oxide layer adhering to the surface of the metal pipe 80 is removed and the metal pipe 80 is cooled. At this time, after the molding is completed, the control unit 70 controls the operation of the blow molding die 13 so as to maintain the state in which the blow molding die 13 and the metal pipe 80 are in contact with each other for a predetermined time, so that the blow molding is performed. The metal pipe 80 may be cooled by the mold 13 and then the metal pipe 80 may be cooled by the blowing gas BA. The cooling rate by the blowing gas BA is slower than the cooling rate by the blow molding die 13. As the blowing gas BA, a high-pressure gas may be blown similarly to the molding, or a normal pressure gas may be blown instead of the high-pressure gas. Moreover, in order to improve cooling performance, you may spray cooling air instead of room temperature air.

  The relationship between the cooling of the metal pipe 80 according to the present embodiment and the temperature will be described with reference to the graph of FIG. In the figure, the region with a gray scale indicates the martensitic transformation region MT. In the drawing, the broken line shows an example of changes in time and temperature when the metal pipe 80 is cooled. When the broken line passes through the martensitic transformation region MT, martensitic transformation occurs. The strength of the metal pipe 80 varies depending on the cooling rate in the region below the martensitic transformation start temperature TS. The metal pipe 80 has a higher hardness as it is cooled at a higher cooling rate. Further, the metal pipe 80 is cooled at a lower cooling rate, the hardness becomes lower, but the toughness becomes higher.

  For example, let L1 be a broken line indicating a temperature change when only cooling is performed by bringing the blow molding die 13 and the metal pipe 80 into contact after the molding is completed. In the present embodiment, the control unit 70 performs cooling by the blow mold 13 until the metal pipe 80 reaches a first temperature (temperature T1 in FIG. 11) that is higher than the martensite transformation start temperature TS. Do. Specifically, as shown in FIG. 11, the control unit 70 controls the operation of the blow molding die 13 so that the temperature of the metal pipe 80 changes along the broken line L1, and blow-molds the metal pipe 80. Contact the mold 13. Then, the control unit 70 opens the blow molding die 13 at the start point P1 to release the contact between the blow molding die 13 and the metal pipe 80, and controls the blow mechanism 60 to use the blowing gas BA. The cooling of the metal pipe 80 and the removal of the oxide layer are started. The start point P1 is a point at which the cooling by the blow molding die 13 is switched to the cooling by the blowing gas BA, the temperature at the start point P1 is T1, and the time (elapsed time from the start of cooling) is H1. After the elapse of time H1, cooling with the blowing gas BA is performed, and the temperature of the metal pipe 80 is cooled at a low cooling rate according to the broken line L2. The temperature T1 at the start point P1 in this example is higher than the martensite transformation start temperature TS. The control unit 70 may start cooling by the cooling unit 90 based on the elapse of time H1 from the start of cooling, and at the timing when it is detected that the temperature of the metal pipe 80 has reached the temperature T1. Cooling by 90 may be started.

  The control unit 70 adjusts the hardenability of the metal pipe 80 based on the timing (start point P1) at which the cooling of the metal pipe 80 with the blowing gas BA is started. The timing of starting the cooling with the blowing gas BA can be changed according to the characteristics required for the molded product, and the time when the temperature of the metal pipe 80 is necessarily higher than the martensite transformation start temperature TS as in the example of FIG. It is not necessary to start at the point, and it may be started at a time when the temperature of the metal pipe 80 is higher than the martensite transformation end temperature TE. For example, the control unit 70 can improve the stretchability while adjusting the starting point P1 and increasing the quenching time with the blowing gas BA, while the strength is reduced. Or the control part 70 can improve intensity | strength by shortening the quenching time by the blowing gas BA. The control unit 70 performs cooling under preset cooling conditions based on characteristics required according to the use of the metal pipe 80 to be formed.

  Unlike the cooling timing illustrated above, the control unit 70 starts blowing the blowing gas BA to the metal pipe 80 by the blow mechanism 60 when the temperature of the metal pipe 80 is equal to or lower than the martensite transformation end temperature TE. The blow mechanism 60 may be controlled to do so. In this case, since the blowing gas BA is sprayed after the temperature of the metal pipe 80 is lowered, the oxide layer is easily removed from the metal pipe 80. That is, in the state where the temperature of the metal pipe 80 is high, the oxide layer may be difficult to peel off from the surface of the metal pipe 80, but spraying is performed after the temperature of the metal pipe 80 becomes lower than the martensite transformation end temperature TE. Thus, the oxide layer can be easily removed.

  Next, operations and effects of the molding apparatus 10 according to the present embodiment will be described.

  According to the molding apparatus 10, even if an oxide layer is generated on the surface of the metal pipe 80 during the molding process, the controller 70 controls the blow mechanism 60 to open the metal pipe 80 after the blow molding die 13 is opened. Spray the blowing gas BA. Thereby, it is possible to suppress the oxide layer from remaining on the surface of the metal pipe 80 by removing the oxide layer attached to the surface of the metal pipe 80. Thereby, it can suppress that the external appearance and material strength of a molded product are influenced, and it becomes possible to improve the quality of a molded product.

  Further, according to the molding apparatus 10, since the blowing gas BA is sprayed on both the inner surface and the outer surface of the metal pipe 80, it is possible to remove the oxide layer adhering to both the inner surface and the outer surface of the metal pipe 80. Thus, the quality of the molded product can be effectively improved.

  Further, according to the molding apparatus 10, when quenching, the blowing mechanism BA starts to be blown by the blow mechanism 60 at a time when the temperature of the metal pipe 80 is higher than the martensite transformation end temperature TE, and the cooling rate is slowed down. Thus, it is possible to perform quenching suitable for the characteristics required for the molded product. That is, the blow mechanism 60 can be used not only for removing the oxide layer but also for adjusting the cooling rate.

  Moreover, according to the shaping | molding apparatus 10, it can be made easy to remove an oxide layer from the metal pipe 80 by spraying, after the temperature of the metal pipe 80 becomes below the martensitic transformation completion temperature TE, Thereby, The oxide layer can be easily removed from the metal pipe 80.

  Further, according to the molding apparatus 10, when the blowing mechanism 60 blows the blowing gas BA onto the metal pipe 80, in the direction intersecting the blowing direction of the blowing gas BA by the blowing mechanism 60 and the mold closing direction of the blow molding die 13. Since the main cavity portion MC is in a closed state, when the blowing gas BA is blown from the blow mechanism 60, the blowing gas BA and the removed oxide layer are not ejected sideways. The oxide layer can be effectively removed.

  In addition, according to the molding apparatus 10, since the vibration or impact is applied to the metal pipe 80 by the pin 91 as the contact portion, the oxide layer can be peeled off from the surface of the metal pipe 80 or can be easily peeled off. Thus, the oxide layer can be removed.

  Moreover, in the shaping | molding apparatus 10, the gas supply part which sprays blowing gas BA is comprised by the blow mechanism 60 which blows in high-pressure gas in the heated metal pipe material 14. As shown in FIG. Thereby, since the blow mechanism 60 for expanding the metal pipe 80 can be used as a gas supply unit, the molding apparatus 10 can be made compact.

  The present invention is not limited to the above-described embodiment.

  For example, the molding apparatus 10 includes the heating mechanism 50 that can perform heat treatment between the upper and lower molds, and heats the metal pipe material 14 using Joule heat generated by energization. However, the present invention is not limited thereto. . For example, the heat treatment may be performed at a place other than between the upper and lower molds, and the heated metal pipe may be carried between the molds. In addition to using Joule heat by energization, radiant heat from a heater or the like may be used, or heating using high-frequency induction current is also possible. Further, the object to be molded is not limited to the metal pipe material, and may be applied to the molding of a metal material having an arbitrary shape. For example, you may apply to shaping | molding of the plate-shaped metal material by normal hot stamp shaping | molding.

  Moreover, you may apply to the shaping | molding apparatus which shape | molds the metal pipe with a flange part. In this case, as the mold, the main cavity for forming the pipe part by contacting the expanded metal pipe material, and the sub part for forming the flange part by crushing a part of the metal pipe material formed by the main cavity. A cavity is used. When forming such a metal pipe with a flange portion, if an oxide layer remains on the inner surface of the metal pipe material, the oxide layer is buried inside the metal pipe material when the flange portion is formed. There is a fear. If an oxide layer is present inside the molded product, the electrical resistance of the portion is lowered, which may cause spot welding defects or the like in the post-processing step. On the other hand, if the mold is opened once before forming the flange, and the flange is formed after removing the oxide layer from the inner surface of the metal pipe material using the gas supply unit, It is possible to suppress the occurrence of inconvenience.

  As the high-pressure gas, a non-oxidizing gas such as nitrogen gas or argon gas or an inert gas can be mainly used. However, although these can make it difficult to generate an oxide layer in the metal pipe, they are expensive. In this respect, if it is compressed air, it is inexpensive, and even if it leaks into the atmosphere, there is no actual harm and handling is extremely easy. Therefore, the blowing process can be executed smoothly.

  The blow mold may be either an anhydrous cold mold or a water-cooled mold. However, the anhydrous cold mold takes a long time to lower the mold to near room temperature after completion of blow molding. In this respect, cooling is completed in a short time with a water-cooled mold. Therefore, a water-cooled mold is desirable from the viewpoint of improving productivity.

  DESCRIPTION OF SYMBOLS 10 ... Molding apparatus, 11 ... Lower mold (metal mold), 12 ... Upper mold (metal mold), 13 ... Blow molding metal mold (metal mold), 14 ... Metal pipe material (metal material), 60 ... Blow mechanism (gas) Supply unit), 70 ... control unit, 80 ... metal pipe, 81 ... drive unit, 82 ... slide, 91 ... pin (contact part), MC ... main cavity part (cavity).

Claims (6)

A molding apparatus for molding a heated metal material by closing a mold,
A gas supply unit for blowing a gas to the metal material and removing an oxide layer attached to the surface of the metal material;
A control unit for controlling the gas supply unit,
The controller is
After the mold is closed, the mold is opened, and the mold is disposed at a position where a gap is formed between the mold and the metal material.
By flowing the said gas to at least the gap, the gas controls the gas supply unit to blow the prior SL metallic material,
A molding apparatus for opening the mold so that the mold is separated from the metal material after the gas is sprayed onto the metal material, rather than the position at the time of the spray . The metal material is a metal pipe material;
The said gas supply part is a shaping | molding apparatus of Claim 1 which sprays the said gas on both the inner surface and the outer surface of the said metal pipe material.   The control unit controls the gas supply unit to start spraying the gas onto the metal material at a time point when the temperature of the metal material is higher than a martensite transformation end temperature. The molding apparatus as described.   The said control part controls the said gas supply part so that the blowing of the said gas to the said metal material may be started at the time of the temperature of the said metal material being below a martensitic transformation completion temperature. Molding equipment.   The said metal mold | die will be in the state which the cavity closed in the cross section seen from the blowing direction of the said gas by the said gas supply part when the said gas supply part sprays the said gas on the said metal material. 2. The molding apparatus according to claim 1. A contact portion that contacts the metal material;
The control unit controls the gas supply unit so as to blow the gas onto the metal material after the mold is opened, and controls the contact unit so as to contact the metal material. Item 6. The molding apparatus according to any one of Items 1 to 5.