JP6704982B2 - Molding equipment - Google Patents

Description

The present invention relates to a forming device for forming a metal pipe with a flange portion.

2. Description of the Related Art Conventionally, there has been known a molding device for molding a metal pipe by supplying gas into a heated metal pipe material to expand the gas. For example, the molding device disclosed in Patent Document 1 includes a pair of molds, a heating unit that heats the metal pipe material, and a gas supply unit that supplies gas into the metal pipe material. In this molding apparatus, gas is supplied from the gas supply unit into the metal pipe material heated by the heating unit to expand the metal pipe material, thereby forming the metal pipe material into a shape corresponding to the shape of the mold. At this time, the heated and expanded metal pipe material is cooled by coming into contact with the mold.

JP, 2003-154415, A

By the way, there are cases where it is required to form a flange portion on a metal pipe. When molding a metal pipe with a flange using the molding equipment as described above, a cavity with a small volume for molding the flange is formed in the mold, and the metal pipe material is expanded and then molded for the flange. A metal pipe with a flange portion can be molded by crushing a part (flange molding portion) of the metal pipe material that has expanded in the cavity. However, in this case, since the metal pipe material comes into contact with the mold and is cooled during expansion molding, the temperature of the flange forming part decreases before it is crushed, and it is possible that the flange part cannot be formed into the target shape. there were. As described above, conventionally, it has been difficult to form a uniform product because it is difficult to control the temperature of the flange forming portion.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a molding apparatus capable of improving the uniformity of molded products.

A molding apparatus according to the present invention is a molding apparatus for molding a metal pipe with a flange portion, in which a gas supply unit for supplying gas into a heated metal pipe material to expand the metal pipe material is in contact with the expanded metal pipe material. A pair of molds having a first cavity part for forming a pipe part of the metal pipe and a second cavity part for forming a flange part by crushing a part of the expanded metal pipe material; A heating unit that heats the second cavity unit.

This molding apparatus includes a heating section that heats the second cavity section. This makes it possible to adjust the temperature of the flange formed by crushing by the second cavity after expansion molding to an appropriate temperature by using the heating unit. As a result, the flange portion can be molded at an appropriate temperature, and the uniformity of the molded product can be improved. As described above, according to this molding apparatus, by providing the heating unit that locally heats the mold, it becomes possible to mold a uniform product.

Further, in the molding apparatus according to the present invention, the heating section may be embedded in at least one of the pair of molds. According to this molding apparatus, since the heating unit comes into contact with the mold, it is possible to improve the responsiveness of temperature control of the mold by the heating unit. Further, it is possible to prevent the oxide scale attached to the metal pipe material from scattering and adhering to the heating portion, which may deteriorate the performance of the heating portion or cause the heating portion to malfunction.

Further, in the molding apparatus according to the present invention, the heating unit is arranged between the pair of molds, and the pair of molds may have a housing unit that houses the heating unit when the molds are closed. According to this molding apparatus, it is possible to improve workability when replacing the heating section.

Further, in the molding apparatus according to the present invention, the heating section may heat the second cavity section by supplying a heating fluid to the second cavity section. According to this forming apparatus, by stopping the supply of the heating fluid after the heating is completed, it is possible to rapidly switch to the cooling of the flange portion which is the next step.

According to the present invention, it is possible to provide a molding apparatus capable of improving the uniformity of molded products.

It is a schematic block diagram of the shaping|molding apparatus which concerns on embodiment of this invention. It is sectional drawing which followed the II-II line shown in FIG. 1, Comprising: It is a schematic cross-sectional view of a blow molding die. FIG. 3 is a schematic vertical sectional view of the blow molding die shown in FIG. 2. It is a figure which shows the manufacturing process by a shaping|molding apparatus, (a) is a figure which shows the state in which the metal pipe material was set in the metal mold|die, (b) is a figure which shows the state in which the metal pipe material is hold|maintained at the electrode is there. It is a figure which shows the blow molding process by a molding apparatus, and the flow after that. It is an enlarged view of an electrode periphery, (a) is a figure which shows the state which the electrode hold|maintained the metal pipe material, (b) is a figure which shows the state which the blow mechanism contacted to the electrode, (c) FIG. 4 is a front view of an electrode. It is a figure which shows operation|movement of a blow molding die and the change of the shape of a metal pipe material, (a) is a figure which shows the state at the time of setting a metal pipe material in a blow molding die, (b) is a blow molding It is a figure which shows the state at the time, and (c) is a figure which shows the state in which the flange part was shape|molded by the press. 9A and 9B are schematic cross-sectional views showing a blow molding die of Modification Example 1, where FIG. 9A is a view showing a state at the time of blow molding, and FIG. 9B is a view showing a state at the time of pressing. 8 is a schematic cross-sectional view showing a blow molding die of Modification Example 2. FIG.

<Structure of molding equipment>
As shown in FIG. 1, a molding apparatus 10 for molding a metal pipe with a flange includes a blow molding die 13 including an upper die 12 and a lower die 11, and a heater (heating for locally heating the blow molding die 13). Part) 20, a slide 82 for moving at least one of the upper die 12 and the lower die 11, a drive portion 81 for generating a driving force for moving the slide 82, and between the upper die 12 and the lower die 11. A pipe holding mechanism (holding portion) 30 that holds the metal pipe material 14 horizontally, a heating mechanism 50 that energizes and heats the metal pipe material 14 held by the pipe holding mechanism 30, and a heated metal pipe material. A blow mechanism (gas supply unit) 60 for blowing high-pressure gas into the control unit 14, a drive unit 81, a heater 20, a pipe holding mechanism 30, a control unit 70 for controlling the heating mechanism 50 and the blow mechanism 60, and a blow molding die 13. And a water circulation mechanism 72 for forcibly cooling with water. 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 blows a high-pressure gas into the heated metal pipe material 14. Take control. In the following description, the pipe of the finished product will be referred to as a metal pipe 80 (see FIG. 5B), and the pipe in the stage of completion will be referred to as a metal pipe material 14.

The lower die 11 is fixed to a large base 15. The lower mold 11 is composed of a large steel block and has a cavity (recess) 16 on its upper surface. Further, an electrode storage space 11a is provided near the left and right ends (left and right ends in FIG. 1) of the lower die 11, and a first electrode 17 configured to be movable up and down by an actuator (not shown) in the space 11a. The second electrode 18 is provided. On the upper surfaces of the first and second electrodes 17 and 18, there are formed semi-circular concave grooves 17a and 18a corresponding to the lower outer peripheral surface of the metal pipe material 14 (see FIG. 6C). The metal pipe material 14 can be placed so that the metal pipe material 14 just fits into the concave grooves 17a and 18a. Further, the front surfaces of the first and second electrodes 17 and 18 (surfaces in the outer direction of the mold) are formed with tapered concave surfaces 17b and 18b, which are depressed toward the concave grooves 17a and 18a by tapering the periphery. There is. A cooling water passage 19 is formed in the lower mold 11, and a thermocouple 21 inserted from the bottom is provided at substantially the center. The thermocouple 21 is supported by a spring 22 so as to be vertically movable.

The pair of first and second electrodes 17 and 18 located on the lower die 11 side also serve as the pipe holding mechanism 30, and can move the metal pipe material 14 up and down between the upper die 12 and the lower die 11. Can be supported horizontally. The thermocouple 21 is merely an example of temperature measuring means, and may be a non-contact temperature sensor such as a radiation thermometer or an optical thermometer. It should be noted that if the correlation between the energization time and the temperature is obtained, the temperature measuring means may be omitted.

The upper mold 12 is a large steel block having a cavity (recess) 24 on the lower surface and having a cooling water passage 25 built therein. The upper die 12 is fixed to the slide 82 at the upper end portion. 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 laterally. The drive unit 81 according to the present embodiment includes a servo motor 83 that generates a driving force for moving the slide 82. The drive unit 81 is configured by a fluid supply unit that supplies a fluid for driving the pressurizing cylinder 26 (operating oil when the 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 servo motor 83 of the drive unit 81 to control the amount of fluid supplied to the pressurizing cylinder 26. The drive unit 81 is not limited to the one that applies the drive force to the slide 82 via the pressurizing cylinder 26 as described above. For example, the drive unit is mechanically connected to the slide 82 to generate the servo motor 83. The driving force for driving may be directly or indirectly applied to the slide 82. 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 in place of the upper mold 12. Further, the drive unit 81 may not include the servo motor 83.

In addition, in the electrode storage space 12a provided near the left and right ends (left and right ends in FIG. 1) of the upper mold 12, as with the lower mold 11, a first structure configured to be movable up and down by an actuator (not shown). The electrode 17 and the second electrode 18 are provided. On the lower surfaces of the first and second electrodes 17 and 18, semicircular arc-shaped grooves 17a and 18a corresponding to the upper outer peripheral surface of the metal pipe material 14 are formed (see FIG. 6C). The metal pipe material 14 can be fitted into the concave grooves 17a and 18a. Further, the front surfaces of the first and second electrodes 17 and 18 (surfaces in the outer direction of the mold) are formed with tapered concave surfaces 17b and 18b, which are depressed toward the concave grooves 17a and 18a by tapering the periphery. There is. That is, when the metal pipe material 14 is sandwiched between the pair of upper and lower first and second electrodes 17 and 18 from above and below, 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 done.

Next, FIG. 2 shows a schematic cross section of the blow molding die 13 as seen from the side surface direction. This is a cross-sectional view of the blow molding die 13 taken along the line II-II in FIG. 1, showing a state of the die position during blow molding. When viewed from the side, both the upper mold 12 and the lower mold 11 have steps formed on their surfaces.

A cavity 24 is formed on the surface 12b of the upper mold 12. The cavity 24 has a rectangular main cavity 24A recessed in the center of the upper die 12 in the left-right direction (left-right direction in FIG. 2), and a rectangular sub-cavity 24B recessed in both left and right sides of the main cavity 24A. , And are formed symmetrically. The sub-cavity 24B communicates with the main cavity 24A and is formed to have a smaller depth than the main cavity 24A. On the other hand, on the surface 11b of the lower mold 11, a cavity 16 having a shape symmetrical with the cavity 24 in the vertical direction is provided. The cavity 16 has a rectangular main cavity 16A recessed in the center of the lower mold 11 in the left-right direction, and rectangular sub-cavities 16B recessed on both the left and right sides of the main cavity 16A, respectively. It is formed symmetrically. The sub-cavity 16B communicates with the main cavity 16A and is formed to have a smaller depth than the main cavity 16A. The main cavity 24A and the main cavity 16A, and the sub-cavity 24B and the sub-cavity 16B are formed such that their surfaces are parallel to each other.

As a result, as shown in FIG. 2, at the mold position during blow molding, a rectangular main cavity part is formed between the surface of the main cavity 24A of the upper mold 12 and the surface of the main cavity 16A of the lower mold 11. (First cavity portion) MC is defined. Further, a rectangular subcavity portion (second cavity portion) SC having a smaller volume than the main cavity portion MC is defined between the surface of the subcavity 24B and the surface of the subcavity 16B. The main cavity portion MC and the sub-cavity portion SC communicate with each other. The main cavity portion MC is a portion for molding the pipe portion 80a of the metal pipe 80, and the sub-cavity portion SC is a portion for molding the flange portion 80b of the metal pipe 80.

A heater 20 is embedded in the upper mold 12 and the lower mold 11 along the sub-cavity SC. In the present embodiment, the heater 20 is embedded in each of the two corners 12c of the upper mold 12 and the two corners 11c of the lower mold 11. The corner portion 12c is a portion that defines the left and right side surfaces of the main cavity 24A and also defines the lower surface of the sub-cavity 24B, and from the lower surface of the main cavity 24A by the difference in depth between the main cavity 24A and the sub-cavity 24B. It is a protruding part. The corner portion 11c is a portion corresponding to the corner portion 12c, and defines the left and right side surfaces of the main cavity 16A and the lower surface of the sub-cavity 16B. In each of the upper mold 12 and the lower mold 11, the heater 20 is arranged in a position symmetrical with respect to the main cavities 24A and 16A. Further, the heaters 20 arranged on the same side in the left-right direction are arranged at positions symmetrical in the vertical direction with respect to the boundary surface between the upper die 12 and the lower die 11.

The heater 20 on the upper die 12 side will be cited to further describe the arrangement position of the heater 20. In the left-right direction, the heater 20 may be arranged at a position overlapping with the left and right side surfaces of the main cavity 24A or outside the left and right side surfaces (sub-cavity 24B side). Alternatively, in the left-right direction, the heater 20 may be arranged at a position overlapping with the left and right side surfaces of the sub-cavity 24B or outside the left and right side surfaces. In addition, as long as heat can be supplied to the sub-cavity portion SC, the heater 20 may be arranged inside the left and right side surfaces of the main cavity 24A in the left-right direction. Further, in the vertical direction, the heater 20 is arranged at a position at least overlapping with the lower surface of the main cavity 24A or below the lower surface (on the surface 12b side of the upper die 12, that is, on the boundary surface side with the lower die 11). Good. Alternatively, in the vertical direction, the heater 20 may be arranged above the lower surface of the main cavity 24A as long as heat can be supplied to the sub-cavity portion SC. Further, depending on the size of the heater 20 and the shape and size of the mold, the heater 20 may be arranged at a position overlapping the lower surface of the sub-cavity 24B or below the lower surface in the vertical direction. Further, the heater 20 may be arranged such that the shortest distance to the sub-cavities 24B is smaller than the shortest distance to the main cavity 24A. The same applies to the heater 20 on the lower die 11 side.

A cartridge-type heater or the like may be used as the heater 20. The heater 20 is controlled by the controller 70 and is used to heat the sub-cavity SC. As shown in FIG. 3, the heater 20 extends in the longitudinal direction of the upper die 12 and the lower die 11 over the entire area of the upper die 12 and the lower die 11 in which the metal pipe material 14 is arranged during molding. It is provided to exist. However, the heater 20 does not have to extend in the region where the sub-cavity portion SC is not provided in the longitudinal direction. This makes it possible to heat the entire sub-cavity SC. The heater 20 does not have to be arranged at a position corresponding to the entire area of the sub-cavity portion SC, but may be provided at a position corresponding to a part thereof. Moreover, you may use the heater 20 divided|segmented into several in the longitudinal direction.

In the present embodiment, the heater 20 is embedded in both the upper mold 12 and the lower mold 11 of the pair of molds, but the heater 20 is embedded in the upper mold 12 and the lower mold 11. It need only be embedded in at least one, and may be embedded in only one of the upper die 12 and the lower die 11. However, by embedding in both, the uniformity of temperature distribution can be improved. Further, the heater 20 only needs to be able to heat the sub-cavity portion SC, and the number, arrangement, etc. are not limited to the example of this embodiment. For example, in the present embodiment, the metal pipe 80 in which the flange portions 80b are formed on both sides of the pipe portion 80a has been described as an example, but the flange portion 80b is formed only on one side of the pipe portion 80a. The metal pipe 80 may be a molding target. In this case, the cavity 24 does not have a symmetrical shape, and the sub-cavities 24B and 16B are provided only on one side of the main cavities 24A and 16A. Therefore, the heater 20 may be embedded only in one of the left and right sides along the sub-cavities 24B, 16B provided in only one of the left and right sides. Further, the shape of the sub-cavity portion SC is not limited to the example of the present embodiment, and may be any shape as long as the flange portion 80b can be molded.

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

The blow mechanism 60 includes a high-pressure gas source 61, an accumulator 62 that stores the high-pressure gas supplied by the high-pressure gas source 61, a first tube 63 extending from the accumulator 62 to the cylinder unit 42, and the first tube 63. The pressure control valve 64 and the switching valve 65, the second tube 67 extending from the accumulator 62 to the gas passage 46 formed in the seal member 44, and the second tube 67. It includes an on/off valve 68 and a check valve 69 that are open. A taper surface 45 is formed at the tip of the seal member 44 so as to be tapered, and the seal member 44 is shaped so that it can be fitted and contacted with the taper concave surfaces 17b and 18b of the first and second electrodes. (See FIG. 6). The seal member 44 is connected to the cylinder unit 42 via the cylinder rod 43, and can move back and forth according to 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 plays a role of supplying the cylinder unit 42 with high-pressure gas having an operating pressure adapted to the pressing force required from the seal member 44 side. The check valve 69 plays a role of preventing the high-pressure gas from flowing backward 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 that stores water, a water pump 74 that pumps up the water accumulated in the water tank 73, pressurizes it, 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, And a pipe 75. Although omitted, a cooling tower for lowering the water temperature and a filter for purifying water may be provided in the pipe 75.

<Operation of molding equipment>
Next, the operation of the molding apparatus 10 will be described. FIG. 4 shows a process from a pipe charging process of charging the metal pipe material 14 as a material to a current heating process of heating the metal pipe material 14 by energizing it. As shown in FIG. 4A, a metal pipe material 14 of a quenchable steel type is prepared, and the metal pipe material 14 is provided on the lower die 11 side by a robot arm or the like (not shown). It is placed on the electrodes 17, 18. Since the first and second electrodes 17 and 18 are formed with the concave grooves 17a and 18a, the metal pipe material 14 is positioned by the concave 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. 4B, an actuator (not shown) that allows the electrodes 17 and 18 to move back and forth is actuated to bring the first and second electrodes 17 and 18 located above and below the electrodes close to each other.・Abut. By this contact, both ends of the metal pipe material 14 are sandwiched by the first and second electrodes 17 and 18 from above and below. Further, the sandwiching is sandwiched by the existence of the concave grooves 17a and 18a formed in the first and second electrodes 17 and 18 so as to be in close contact with the entire circumference of the metal pipe material 14. 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 configuration may be such that the first and second electrodes 17 and 18 are in contact with a part of the metal pipe material 14 in the circumferential direction. ..

Subsequently, the control unit 70 controls the heating mechanism 50 to heat the metal pipe material 14. Specifically, the control unit 70 turns on the switch 53 of the heating mechanism 50. Then, electric power is supplied to the metal pipe material 14 from the power source 51, and the resistance existing in the metal pipe material 14 causes the metal pipe material 14 itself to generate heat (Joule heat). At this time, the measured value of the thermocouple 21 is constantly monitored, and energization is controlled based on this result.

FIG. 5 shows a flow of obtaining a metal pipe 80 with a flange in which a flange portion 80b is formed on a pipe portion 80a as a finished product by forming a flange by pressing on the metal pipe material 14 after blow molding. First, the control unit 70 turns on the heater 20 to heat the sub-cavity portion SC (details of this point will be described later). Then, the control unit 70 controls the blow mechanism 60 so as to supply the gas into the metal pipe material 14 held between the upper die 12 and the lower die 11 by the pipe holding mechanism 30 to remove the metal pipe material 14. Expand and mold. Subsequently, the control unit 70 turns off the heater 20 to stop the heating of the sub-cavity part SC, and then pushes a part of the expansion-molded metal pipe material 14 with the sub-cavity parts SC of the upper mold 12 and the lower mold 11. The drive portion 81 is controlled so as to be crushed, and the flange portion 80b is molded. Specifically, the blow molding die 13 is closed while the sub-cavity SC is heated by the heater 20, and the metal pipe material 14 is placed and sealed in the cavity of the blow molding die 13. Then, the cylinder unit 42 is operated to seal both ends of the metal pipe material 14 with the seal members 44 which are a part of the blow mechanism 60 (see also FIG. 6). Note that this seal does not directly contact the seal members 44 with both end faces of the metal pipe material 14 to seal them, but indirectly through the tapered concave surfaces 17b and 18b formed on the first and second electrodes 17 and 18, respectively. To be done. By doing so, it is possible to improve the sealing performance because a wide area can be sealed, and at the same time, it is possible to prevent wear of the sealing member due to repeated sealing operations, and to effectively prevent crushing of both end surfaces of the metal pipe material 14. ing. After the sealing is completed, a high pressure gas is blown into the metal pipe material 14 to deform the metal pipe material 14 softened by heating so as to follow the shape of the cavity. Then, after turning off the heater 20 to stop the heating of the sub-cavity portion SC, a pressing operation for forming the flange portion 80b is performed on the blow-molded metal pipe material 14 (details of this point will be described later). .), the metal pipe 80 having the pipe portion 80a and the flange portion 80b is completed as a finished product.

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

Then, the outer peripheral surface of the metal pipe material 14 blown and expanded is brought into contact with the cavity 16 (mainly, the main cavity 16A) of the lower mold 11 to be rapidly cooled, and at the same time, the cavity 24 (mainly of the upper mold 12). Is cooled by contact with the main cavity 24A (the upper die 12 and the lower die 11 have a large heat capacity and are controlled to a low temperature, so when the metal pipe material 14 comes into contact, the heat of the pipe surface is immediately transferred to the mold side. It will be deprived.) and then quenched. Such a cooling method is called mold contact cooling or mold cooling. Immediately after being quenched, austenite transforms into martensite. In the latter half of cooling, the cooling rate became smaller, so that the martensite is transformed into another structure (troustite, sorbite, etc.) by recuperation. Therefore, it is not necessary to perform a separate tempering process.

Here, the reason why the heater 20 heats the sub-cavity portion SC during blow molding will be described. As described above, the blow-molded and expanded metal pipe material 14 is cooled by coming into contact with the upper die 12 and the lower die 11. For this reason, before pressing and crushing a part of the metal pipe material 14, the temperature of the flange-molded portion of the metal pipe material 14 that becomes the flange portion 80b is lowered, and the flange portion 80b is formed in the target shape. There was a possibility that it could not be molded. Therefore, in the molding apparatus 10 of the present embodiment, the sub-cavity SC is heated by the heater 20 during blow molding. As a result, it is possible to prevent the flange-molded portion from coming into contact with the sub-cavity portion SC during blow molding and lowering the temperature of the flange-molded portion, and it is possible to mold the flange portion 80b at an appropriate temperature. In the present embodiment, the control unit 70 turns on the heater 20 before the start of blow molding and turns off the heater 20 when the mold is closed after the completion of blow molding, so that the sub-cavity SC is heated during blow molding. While maintaining the state, the heater 20 is controlled so that the sub-cavity portion SC is not heated when the flange portion 80b is molded.

In the present embodiment, the heater 20 controls the heating of the sub-cavity portion SC before the start of blow molding until the completion of blow molding, but the heating timing is not limited to this. That is, the heating may be performed at least before the time when the blow molding is started and the flange-molded portion contacts the sub-cavity portion SC. For example, the heating may be controlled at the same time as the start of the blow molding, or the blow molding may be performed. The heater 20 may be turned on and heated before the start of molding, and the heater 20 may be turned off after the start of blow molding. Further, the heater 20 may be turned on after the blow molding. For example, the heater 20 may be turned on when molding the flange portion 80b in the sub-cavity portion SC.

Next, with reference to FIG. 7, a state of molding by the upper mold 12 and the lower mold 11 will be described in detail. In the following description, of the metal pipe material 14 in the process of forming, a portion corresponding to the pipe portion 80a of the metal pipe 80 according to the finished product is referred to as a "pipe formed portion 14a", and a portion corresponding to the flange portion 80b. Is referred to as "flange-molded portion 14b". As shown in FIGS. 7A and 7B, in the molding apparatus 10 according to the present invention, blow molding is performed with the upper mold 12 and the lower mold 11 completely closed (clamped). I'm not there. That is, the blow molding is performed in the state where the sub-cavity portion SC is formed beside the main cavity portion MC by maintaining the constant separation state. In this state, the main cavity portion MC is formed between the surface of the main cavity 24A and the surface of the main cavity 16A. Further, sub-cavity portions SC are formed on the left and right sides of the main cavity portion MC between the surface of the sub-cavity 24B and the surface of the sub-cavity 16B. The main cavity portion MC and the sub-cavity portion SC communicate with each other. Therefore, as shown in FIG. 7B, the metal pipe material 14 softened by heating and injected with the high-pressure gas enters not only the main cavity portion MC but also the sub-cavity portion SC and expands. As described above, the heater 20 is turned on and the sub-cavity SC is heated during the blow molding. In the example shown in FIG. 7, since the main cavity portion MC is configured to have a rectangular cross section, the metal pipe material 14 is blow-molded in accordance with the shape to be shaped to have a rectangular cross section. In addition, the said part respond|corresponds to the pipe molding part 14a used as the pipe part 80a. However, the shape of the main cavity portion MC is not particularly limited, and any shape such as a circle, an ellipse, or a polygon may be adopted according to a desired shape. Further, since the main cavity portion MC and the sub-cavity portion SC communicate with each other, part of the metal pipe material 14 enters the sub-cavity portion SC. This portion corresponds to the flange-molded portion 14b that becomes the flange portion 80b by being crushed.

As shown in FIG. 7C, the upper mold 12 and the lower mold 11 that are separated are brought close to each other after or during the blow molding. By this operation, the volume of the sub-cavity SC becomes small, the internal space of the flange-molded portion 14b disappears, and the sub-cavity portion 14b is folded. That is, when the upper die 12 and the lower die 11 approach each other, the flange-formed portion 14b of the metal pipe material 14 that has entered the sub-cavity portion SC is pressed and crushed. As a result, the outer peripheral surface of the metal pipe material 14 is crushed and crushed along the longitudinal direction of the metal pipe material 14 to form a flange forming portion 14b (in this state, the metal pipe material 14 is the metal pipe 80 as a finished product). (It has the same shape as the above). The time from the blow molding to the completion of press molding of the flange portion 80b is approximately 1 to 2 seconds, depending on the type of the metal pipe material 14. As described above, during this press molding, the heater 20 is turned off and the heating of the sub-cavity portion SC is stopped. In the example shown in FIG. 7, when the press molding is completed, the surface 12b of the upper mold 12 contacts the surface 11b of the lower mold 11, and the upper mold 12 and the lower mold 11 cannot be brought closer to each other. In this state, a gap corresponding to the thickness of the crushed flange molding portion 14b (that is, the flange portion 80b) is formed between the surface of the sub-cavity 24B and the surface of the sub-cavity 16B.

Further, due to the approach of the upper mold 12 and the lower mold 11 after blow molding, not only the flange-molded portion 14b of the metal pipe material 14 that has entered the sub-cavity portion SC but also the metal pipe material 14 of the main cavity portion MC The pipe molding portion 14a is also crushed, but since it is heated and softened, it is possible to finish the product without sagging or twisting by adjusting the mold closing speed, the compressed gas, or the like.

(Modification 1)
Next, with reference to FIG. 8, a molding apparatus according to Modification 1 will be described. The molding apparatus according to the modified example 1 is different from the molding apparatus 10 of the above-described embodiment in that the heater is arranged between the upper mold and the lower mold. Hereinafter, differences from the above-described embodiment will be particularly described, and the same configurations will be denoted by the same reference numerals and description thereof will be omitted.

As shown in FIG. 8, in the blow molding die 113 of the modified example 1, a rectangular shape is formed on each of the left and right outer sides of the surface 112b of the upper die 112 (the side opposite to the main cavity 24A with respect to the sub cavity 24B). A recess 112A is formed. Further, a rectangular recess 111A is formed on each of the left and right outer sides of the sub-cavity 16B on the surface 111b of the lower mold 111. As shown in FIG. 8B, these recesses 112A and 111A define a housing portion (housing space) 130 between the upper mold 112 and the lower mold 111 when the mold is closed.

In the molding apparatus according to the modified example 1, the heater 120 (heating unit) is arranged between the upper mold 112 and the lower mold 111. The heater 120 is fixed by supporting both ends on the outer side in the longitudinal direction of the blow molding die 113, and is installed separately from the blow molding die 113. The heater 120 is accommodated in the accommodating portion 130 so that the heater 120 does not contact (interfere) with the blow molding die 113 when the mold is closed (press molding). The heater 120 is similar to the heater 20 of the above embodiment in that it is used for locally heating the blow molding die 113 during blow molding. That is, the control unit 70 turns on the heater 120 before the blow molding and turns off the heater 120 when the mold is closed after the blow molding is completed, so that the sub-cavity SC is heated during the blow molding, and the flange The heater 120 may be controlled such that the sub-cavity portion SC is not heated when the portion 80b is molded. In addition, as the molding apparatus of the modified example 1, the heater 120 is described so as not to contact the blow molding die 113 when the mold is closed, but the heater 120 may contact the blow molding die 113. It may be provided.

(Modification 2)
Next, with reference to FIG. 9, a molding apparatus according to Modification 2 will be described. The molding apparatus according to the second modification differs from the molding apparatus 10 of the above-described embodiment in that it includes a heating fluid supply unit that supplies a heating fluid instead of the heater. Hereinafter, differences from the above-described embodiment will be particularly described, and the same configurations will be denoted by the same reference numerals and description thereof will be omitted.

As shown in FIG. 9, in the blow molding die 213 of the modified example 2, the upper mold 212 and the lower mold 211 are provided with a heating fluid supply unit 220 (heating unit). The heating fluid supply unit 220 includes a piping portion 221 formed in the corners 212c and 111c, through which the heating fluid (high-temperature air) flows, and a blowing portion that extends from the piping portion 221 and opens on the surfaces of the sub-cavities 24B and 16B. 223 and. In the molding apparatus according to Modification 2, the subcavity SC is heated by supplying (blowing) a heating fluid from the outlet of the outlet 223 instead of the heater 20 and the heater 120 described above. The heating fluid may be either a gas or a liquid, and is preferably an inert gas such as nitrogen or argon gas. In the molding apparatus according to the modified example 2, the control unit 70 supplies the heating fluid to the heating fluid supply unit 220 after the blow molding so that the sub-cavity SC is heated during the blow molding. The unit 220 is controlled. At the time of blow molding (when the mold is closed), not only the supply of the heating fluid from the heating fluid supply unit 220 may be stopped, but also the cooling fluid (refrigerant) may be supplied to cool the periphery of the outlet. .. As the refrigerant, for example, gas can be used.

Next, the operation and effect of the molding apparatus 10 according to this embodiment will be described.

When the metal pipe 80 with the flange portion 80b is molded by using the molding device of the prior art, the flange molding portion 14b of the metal pipe material 14 is brought into contact with the sub-cavity SC to be cooled during the blow molding, thereby performing the press molding. There is a possibility that the temperature of the flange-molded portion 14b will drop before it is crushed by and the flange portion 80b cannot be molded into the target shape.

In this respect, the molding apparatus 10 according to the present embodiment includes the heater 20 that heats the sub-cavity portion SC. The flange portion 80b can be molded at an appropriate temperature, and the uniformity of the molded product (metal pipe 80) can be improved. As described above, according to the molding apparatus 10, by providing the heater 20 that locally heats the blow molding die 13, it is possible to mold a uniform product.

According to the molding apparatus 10 according to the present embodiment, the temperature of the sub-cavity portion SC during blow molding (during expansion molding) is adjusted by heating with the heater 20 (heater 120, heating fluid supply unit 220). Therefore, it is possible to prevent the flange forming portion 14b from coming into contact with the sub-cavity portion SC during blow molding and the temperature of the flange forming portion 14b lowering.

Further, in the molding apparatus 10, since the heater 20 is embedded in at least one of the upper mold 12 and the lower mold 11, the heater 20 contacts the upper mold 12 or the lower mold 11, and the heater 20 causes the upper mold 12 or the lower mold 11 to contact. The effect of improving the temperature control response of the mold 11 is obtained. Further, it is possible to prevent the scale attached to the pipe material 14 from scattering and adhering to the heater 20, which lowers the performance of the heater 20 and causes the heater 20 to malfunction. In the molding apparatus of the modified example 1, the heater 110 is arranged between the blow molding dies 13 (between the upper mold 12 and the lower mold 11 ), and the blow molding dies 13 keep the heater 110 when the molds are closed. Since the housing portion 130 for housing the heater 20 is provided, it is possible to obtain an effect of improving workability when replacing the heater 20. In the molding apparatus of Modification Example 2, the heating fluid supply unit 220 heats the sub-cavity SC by supplying the heating fluid to the sub-cavity SC, so that the supply of the heating fluid is stopped after the heating is completed. As a result, it is possible to rapidly switch to the next step of cooling the flange portion.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and may be modified without departing from the scope of the claims and applied to other embodiments. Good.

The molding apparatus 10 includes the heating mechanism 50 capable of performing heat treatment between the upper and lower molds, and heats the metal pipe material 14 using Joule heat generated by energization, but the present invention is not limited thereto. For example, the heat treatment may be performed in 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 due to energization, radiant heat from a heater or the like may be used, or high frequency induction current may be used for heating.

As the high-pressure gas, a non-oxidizing gas such as nitrogen gas or argon gas or an inert gas can be mainly adopted, but these are expensive although they can make it difficult to generate oxide scale in the metal pipe. In this respect, compressed air is inexpensive unless it causes a serious problem due to the generation of oxide scale, and even if it leaks into the atmosphere, it is not harmful and is extremely easy to handle. Therefore, the blowing process can be smoothly performed.

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

10... Molding device, 11... Lower mold, 12... Upper mold, 13... Blow molding mold (pair of molds), 14... Metal pipe material, 14a... Pipe molding part, 14b... Flange molding part, 16, 24... Cavity, 16A, 24A... Main cavity, 16B, 24B... Sub-cavity, 20, 120... Heater (heating part), 30... Pipe holding mechanism (holding part), 50... Heating mechanism, 60... Blow mechanism (gas supply part) , 70... control part, 80... metal pipe, 80a... pipe part, 80b... flange part, 81... drive part, 82... slide, 220... heating fluid supply part (heating part), MC... main cavity part (first Cavity part), SC... Sub-cavity part (second cavity part).

Claims (5)

A forming device for forming a metal pipe with a flange portion,
A first cavity portion for forming a pipe portion of the metal pipe by bringing the expanded metal pipe material into contact with it in a heated state, and forming the flange portion by crushing a part of the expanded metal pipe material A pair of molds having a second cavity part for
A heating unit that heats the second cavity unit,
The mold is provided with a cooling means for quenching,
The said heating part makes the temperature of a flange molding surface higher than the pipe molding surface in the said metal mold at least when forming the said flange part. The molding apparatus according to claim 1, wherein the heating unit performs heating at least before the expanded metal pipe comes into contact with the second cavity unit. The molding apparatus according to claim 2, wherein the heating section is controlled so that the second cavity section is not heated during molding of the flange section. The molding device according to claim 1, wherein the heating unit is embedded in at least one of the pair of molds. The molding apparatus according to claim 1, wherein the heating section heats the second cavity section by supplying a heating fluid to the second cavity section.

Images