JP6875341B2 - Molding system and molding method - Google Patents

Description

The present invention relates to a molding system and a molding method for molding a metal pipe.

Conventionally, a molding system that performs molding by supplying a fluid into a metal pipe material and expanding it is known. For example, the molding system shown in Patent Document 1 includes an upper mold and a lower mold that are paired with each other, a holding portion that holds a metal pipe material between the upper mold and the lower mold, and a metal pipe material held by the holding portion. It is provided with a fluid supply unit that supplies fluid inside. In this molding apparatus, the metal pipe material is expanded and molded into a shape corresponding to the shape of the mold by supplying a fluid into the metal pipe material held between the upper mold and the lower mold. Can be done. Such a molding method is called hydroforming.

Japanese Unexamined Patent Publication No. 2004-33798

Here, in the above-mentioned molding system, the nozzle of the fluid supply unit is inserted into the end portion of the metal pipe material held by the holding unit to supply the fluid to the inside of the metal pipe material. At this time, the end portion of the metal pipe material is expanded by pressing the end portion of the metal pipe material against the holding portion with the nozzle. As a result, the sealing property between the nozzle and the holding portion is ensured. However, in the above-mentioned molding system, the end portion of the metal pipe material may not expand satisfactorily due to the pressing of the nozzle, and sufficient sealing property may not be ensured.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a molding system and a molding method capable of improving the sealing property when supplying a fluid to a metal pipe material. To do.

The molding system according to the present invention is a molding system that expands and molds a metal pipe in a mold, and supplies at least a heating portion that heats an end portion of the metal pipe material and a fluid into the metal pipe material. The fluid supply unit includes a fluid supply unit for expansion, a heating unit, and a control unit for controlling the fluid supply unit. The fluid supply unit has a nozzle for supplying fluid from the end of the metal pipe material to the inside, and the control unit has a nozzle. Control the heating section to heat the end of the metal pipe material, at least prior to the supply of fluid by the fluid supply section, by pressing force by pressing the nozzle against the end of the metal pipe material, or the nozzle. Controls the fluid supply so that the end of the metal pipe material is expanded by the expansion force of supplying the fluid to the end of the metal pipe material.

In the molding system according to the present invention, the control unit controls the heating unit so as to heat the end portion of the metal pipe material at least before the fluid supply by the fluid supply unit. Therefore, at least in the pre-stage of fluid supply by the fluid supply unit, the end portion of the metal pipe material is easily deformed by being heated by the heating unit. This condition facilitates the metal pipe material by the pressing force of pressing the nozzle against the end of the metal pipe material or by the expansion force of the nozzle supplying fluid to the end of the metal pipe material. It is possible to widen the end of the. Therefore, the nozzle can ensure sufficient airtightness through the extension of the metal pipe material. From the above, according to the present invention, it is possible to improve the sealing property when supplying a fluid to a metal pipe material.

Further, the molding system according to the present invention further includes a holding portion for holding the end end side of the metal pipe material, and the control unit is made of metal by pressing the end portion of the metal pipe material against the holding portion with a nozzle. The fluid supply may be controlled to widen the ends of the pipe material. According to this configuration, the nozzle and the holding portion can be sealed via the extension portion of the metal pipe material.

Further, in the molding system according to the present invention, the control unit controls the fluid supply unit so that the end portion of the metal pipe material is expanded by the expansion force caused by the nozzle supplying the fluid to the end portion of the metal pipe material. The nozzle may have a receiving portion that surrounds the end of the metal pipe material from the outer peripheral side and receives the expanded end of the metal pipe material when supplying the fluid. According to this configuration, the receiving portion of the nozzle receives the expanding portion of the metal pipe material, so that the receiving portion and the expanding portion can be sealed.

The molding method according to the present invention is a molding method in which a metal pipe is expanded and molded in a mold, and is a heating step of heating at least the end portion of the metal pipe material and an expansion step of expanding the end portion of the metal pipe material. A fluid supply step of supplying a fluid into the metal pipe material to expand the metal pipe material and a molding step of bringing the expanded metal pipe material into contact with a mold to form a metal pipe are provided, and the heating step is at least an expansion step. And by a pressing force by pressing a nozzle that supplies fluid to the end of the metal pipe material against the end of the metal pipe material, or by the nozzle at the end of the metal pipe material, which is performed prior to the fluid supply process. The expansion force of the fluid supply expands the ends of the metal pipe material.

According to the molding method according to the present invention, the same actions and effects as those of the above-mentioned molding system can be obtained.

According to the present invention, it is possible to improve the sealing property when supplying a fluid to a metal pipe material.

It is a schematic block diagram of the molding system which concerns on embodiment of this invention. FIG. 5 is a cross-sectional view taken along the line II-II shown in FIG. 1, which is a schematic cross-sectional view of a blow molding die. It is a figure which shows the manufacturing process by a molding system, (a) is a figure which shows the state which the metal pipe material is set and held in the mold, (b) is the figure which pressed the nozzle against the end of the metal pipe material. The figure which shows the state, (c) is the figure which shows the state which performed the blow molding. It is an enlarged view around the nozzle. It is an enlarged view of the nozzle which concerns on a modification. It is a figure which shows the operation of the nozzle which concerns on the modification.

<Structure of molding system>
As shown in FIGS. 1 to 3, the molding system 100 for molding a metal pipe includes a blow molding die (die) 1 composed of an upper die 3 and a lower die 2, an upper die 3 and a lower die 2. A holding unit 4 that holds the metal pipe material 14 horizontally, a heating unit 6 that heats the metal pipe material 14, a fluid supply unit 10 that supplies fluid into the metal pipe material 14 and expands the metal pipe material 14, and blow molding. It is configured to include an operation of the mold 1, a holding unit 4, a heating unit 6, and a control unit 20 for controlling the fluid supply unit 10. In the following description, the molded pipe will be referred to as a metal pipe 80 (see FIG. 2B), and the pipe in the middle of completion will be referred to as a metal pipe material 14.

The lower mold 2 is composed of a large steel block, and has a recess 2a on the upper surface thereof. The lower mold 2 may be fixed to, for example, a base (not shown). The upper mold 3 is composed of a large steel block, and has a recess 3a on the upper surface thereof. The upper end of the upper die 3 may be fixed to a slide or the like driven by a drive unit (not shown).

FIG. 2 is a schematic cross section of the blow molding die 1 as viewed from the side surface direction. This is a cross-sectional view of the blow molding die 1 along the line II-II in FIG. 1, and shows the state of the mold position at the time of blow molding. As shown in FIG. 2, a rectangular recess 2a is formed on the upper surface of the lower mold 2. On the lower surface of the upper mold 3, a rectangular recess 3a is formed at a position facing the recess 2a of the lower mold 2. When the blow molding die 1 is closed, the concave portion 2a of the lower mold 2 and the concave portion 3a of the upper mold 3 are combined to form a main cavity portion MC which is a rectangular space. As shown in FIG. 2 (a), the metal pipe material 14 arranged in the main cavity portion MC comes into contact with the inner wall surface of the main cavity portion MC as shown in FIG. 2 (b) by expanding, and the metal pipe material 14 is said to be in contact with the inner wall surface of the main cavity portion MC. It is molded into the shape of the main cavity MC (here, a rectangular cross section).

The holding portions 4 are provided near the left and right ends (left and right ends in FIG. 1) of the lower mold 2, the first electrode 11 and the second electrode 12, and the left and right ends (left and right ends in FIG. 1) of the upper mold 3. The first electrode 11 and the second electrode 12 are provided. The first electrode 11 and the second electrode 12 are configured to be able to move up and down by an actuator (not shown). Semi-circular concave grooves 11a, 12a corresponding to the lower outer peripheral surface of the metal pipe material 14 are formed on the upper surfaces of the lower first and second electrodes 11 and 12, the concave grooves 11a, The metal pipe material 14 can be placed so as to fit into the portion 12a. Further, the front surfaces of the first and second electrodes 11 and 12 (surfaces in the outer direction of the mold) are formed with tapered concave surfaces 11b and 12b whose periphery is inclined in a tapered shape toward the concave grooves 11a and 12a. There is. Further, on the lower surfaces of the upper first and second electrodes 11 and 12, semicircular concave grooves 11a and 12a corresponding to the upper outer peripheral surface of the metal pipe material 14 are formed, and the concave grooves 11a and 12a are formed. The metal pipe material 14 can be fitted to the metal pipe material 14. Further, the front surfaces of the first and second electrodes 11 and 12 (surfaces in the outer direction of the mold) are formed with tapered concave surfaces 11b and 12b whose periphery is inclined in a tapered shape toward the concave grooves 11a and 12a. There is. That is, when the metal pipe material 14 is sandwiched between the upper and lower pairs of the first and second electrodes 11 and 12 from the vertical direction, the outer circumference of the metal pipe material 14 can be surrounded so as to be in close contact with the entire circumference. Has been done.

Further, in the present embodiment, the first electrode 11 and the second electrode 12 also function as a heating unit 6 for heating the metal pipe material 14. Specifically, the first electrode 11 and the second electrode 12 are connected to a power source (not shown), and the metal pipe material 14 is heated by supplying electric power to the metal pipe material 14. The heating unit 6 can heat at least the ends 14a and 14b of the metal pipe material 14.

The fluid supply unit 10 includes nozzles 7 and 8 that supply fluid from the ends 14a and 14b of the metal pipe material 14 to the inside. The nozzles 7 and 8 are connected to the cylinder unit via a cylinder rod (not shown), and can move forward and backward in accordance with the operation of the cylinder unit. The tips of the nozzles 7 and 8 are inserted from the ends 14a and 14b of the metal pipe material 14, respectively, and supply a fluid to the inside of the metal pipe material 14. As a result, the metal pipe material 14 arranged inside the blow molding die 13 can be expanded. As the fluid supplied by the nozzles 7 and 8, a fluid such as water or oil can be adopted. The nozzles 7 and 8 are provided with conical tapered surfaces 7b and 8b so as to taper toward the tip portions 7a and 8a. The detailed structure of the nozzles 7 and 8 will be described together with the operation description by the control unit 20 described later.

<Operation of molding system>
Next, the operation of the molding system 100 will be described. FIG. 3 shows from a pipe charging step of charging the metal pipe material 14 as a material to a step of expanding and molding the metal pipe material to form a metal pipe 80. As shown in FIG. 3A, a metal pipe material 14 is prepared, and the metal pipe material 14 is used on the first and second electrodes 11 and 12 provided on the lower mold 2 side by a robot arm or the like (not shown). Place on. Since the concave grooves 11a and 12a are formed in the first and second electrodes 11 and 12, the metal pipe material 14 is positioned by the concave grooves 11a and 12a. Next, the control unit 20 (see FIG. 1) controls the holding unit 4 to cause the holding unit 4 to hold the metal pipe material 14. Specifically, as shown in FIG. 3A, an actuator that allows the electrodes 17 and 18 to move forward and backward is operated to bring the first and second electrodes 11 and 12 located above and below the electrodes 11 and 12 into close contact with each other. .. By this contact, both ends of the metal pipe material 14 are sandwiched by the first and second electrodes 11 and 12 from above and below. Further, this sandwiching is held in such a manner that the metal pipe material 14 is brought into close contact with the metal pipe material 14 due to the presence of the concave grooves 11a and 12a formed in the first and second electrodes 11 and 12. However, the configuration is not limited to the structure in which the metal pipe material 14 is in close contact with the entire circumference, and the first and second electrodes 11 and 12 may be in contact with a part of the metal pipe material 14 in the circumferential direction. .. Further, in a state where the first and second electrodes 11 and 12 hold the metal pipe material 14, a part of the metal pipe material 14 on the end 14a and 14b side is at least an outer end of the groove 11a and 12a. Protrudes to the outside from. That is, the metal pipe material 14 is held by the holding portion 4 in a state where a gap is formed between a part of the end portions 14a and 14b of the metal pipe material 14 and the tapered concave surfaces 11b and 12b.

Subsequently, the control unit 20 heats the metal pipe material 14 by controlling the heating unit 6 (heating step). Specifically, the control unit 20 turns on the switch of the heating unit 6. Then, electric power is supplied from the power source (not shown) to the metal pipe material 14 via the first and second electrodes 11 and 12, and the metal pipe material 14 itself generates heat due to the resistance existing in the metal pipe material 14 (Joule). heat). As a result, the heating unit 6 can heat at least the end portions 14a and 14b of the metal pipe material 14 (in the present embodiment, the entire metal pipe material 14). Further, the heating step by the heating unit 6 is performed at least before the fluid supply by the fluid supply unit 10. Next, the blow molding die 1 is closed with respect to the heated metal pipe material 14, and the metal pipe material 14 is placed and sealed in the cavity of the blow molding die 1.

After that, as shown in FIG. 3B, the control unit 20 presses the nozzles 7 and 8 of the fluid supply unit 10 against the ends 14a and 14b of the metal pipe material 14 by pressing the metal pipe material 14 to the metal pipe material 14. The nozzles 7 and 8 of the fluid supply unit 10 are controlled so as to expand the ends 14a and 14b (expansion step). Further, the control unit 20 expands the end portions 14a, 14b of the metal pipe material 14 by pressing the end portions 14a, 14b of the metal pipe material 14 against the holding portion 4 with the nozzle, so that the fluid supply unit 10 expands. To control.

Here, the configuration of the nozzle 8 will be described in detail with reference to FIG. Since the nozzle 7 has the same configuration as the nozzle 8, the description thereof will be omitted. Further, while FIGS. 1 and 3 are schematic configuration diagrams of the molding system 100, FIG. 4 is a diagram showing the configuration of the nozzle 8 in more detail, so that some parts have different shapes. In the following description, it is assumed that the metal pipe material 14 and the central axis of the nozzle 8 are aligned with each other. As shown in FIG. 4, the nozzle 8 has a large diameter portion 8A formed on the base end side (outside with respect to the blow molding mold 1) and the large diameter portion 8A toward the tip side (blow molding mold 1 side). It includes a tapered portion 8B that is tapered, and a small diameter portion 8C that extends from the tapered portion 8B to the tip side. The diameter of the small diameter portion 8C is set to be smaller than the inner diameter of the metal pipe material 14 and the inner diameter of the concave groove 12a in the stage before blow molding or expansion. The diameter of the large diameter portion 8A is set to be larger than the inner diameter of the outer end portion (the portion having the largest inner diameter) of the tapered concave surface 12b. The tapered surface 8b of the tapered portion 8B is inclined so as to be substantially parallel to the tapered concave surface 12b of the second electrode 12.

With such a configuration, when the nozzle 8 is moved so as to insert the small diameter portion 8C of the nozzle 8 into the inside from the end portion 14b of the metal pipe material 14 before expansion (state of FIG. 3A), the end portion 14b Abuts on the tapered surface 8b of the nozzle 8. At this time, since the end portion 14b of the metal pipe material 14 is in a state of being heated by the heating portion 6, it is in a state of being easily deformed. Therefore, when the nozzle 8 is further moved, a part of the metal pipe material 14 on the end portion 14b side is deformed so that the diameter increases along the shape of the tapered surface 8b. Then, the expanded portion 14d of the metal pipe material 14 expanded by pressing the tapered surface 8b is pressed against the tapered concave surface 12b of the second electrode 12 by the tapered surface 8b of the nozzle 8. That is, the tapered surface 8b of the nozzle 8 is pressed against the tapered concave surface 12b of the second electrode 12 via the expansion portion 14d of the metal pipe material 14. As a result, the sealing property between the tapered surface 8b of the nozzle 8 and the tapered concave surface 12b of the second electrode 12 is ensured.

As shown in FIG. 3B, the end portions 14a and 14b on both sides of the metal pipe material 14 are in a state of being sealed by the nozzles 7 and 8. After the sealing is completed, the control unit 20 blows a high-pressure fluid into the metal pipe material 14 by controlling the fluid supply unit 10 (fluid supply step). As a result, the expanded metal pipe material 14 is brought into contact with the blow molding die 13, and the metal pipe material 14 is deformed so as to conform to the shape of the blow molding die 13 to form the metal pipe 80 (molding step). ).

Since the metal pipe material 14 is softened by heating the heating unit 6, expansion molding becomes easy.

Next, the operation / effect of the molding system 100 according to the present embodiment will be described.

Here, as a molding system according to a comparative example, a sealing property is ensured by directly contacting the tapered concave surfaces 11b and 12b of the first and second electrodes 11 and 12 with the tapered surfaces 7b and 8b of the nozzles 7 and 8. Will be described. In this case, when the metal pipe material 14 is held by the holding portion 4, the end portions 14a and 14b do not protrude outward from the first and second electrodes 11 and 12. In the molding system according to the comparative example, the first and second electrodes 11 and 12 and the nozzles 7 and 8 are in direct contact with each other, so that the durability of both electrodes is required to ensure sufficient sealing performance. .. That is, if at least one of the tapered concave surfaces 11b and 12b and the tapered surfaces 7b and 8b is worn, it may not be possible to secure sufficient sealing performance.

Further, as a molding system according to another comparative example, similarly to the molding system 100 according to the present embodiment, the end portions 14a and 14b of the metal pipe material 14 are pressed against the holding portion 4 by pressing the ends 14a and 14b with the nozzles 7 and 8. A metal pipe material 14 that expands by pressure but does not have a heating unit 6 will be described. In the molding system according to such a comparative example, the ends 14a and 14b of the metal pipe material 14 may not spread well due to the pressing of the nozzles 7 and 8, and sufficient sealing property may not be ensured.

On the other hand, in the molding system 100 according to the present embodiment, the control unit 20 heats the end portions 14a and 14b of the metal pipe material 14 at least in a stage prior to the supply of the fluid by the fluid supply unit 10. The unit 6 is controlled. Therefore, at least in the pre-stage of fluid supply by the fluid supply unit 10, the ends 14a and 14b of the metal pipe material 14 are easily deformed by being heated by the heating unit 6. In such a state, the end portions 14a and 14b of the metal pipe material 14 can be easily expanded by the pressing force of pressing the nozzles 7 and 8 against the end portions 14a and 14b of the metal pipe material 14. Become. Therefore, the nozzles 7 and 8 can secure sufficient airtightness through the expansion portions 14c and 14d of the metal pipe material 14. From the above, according to the molding system 100 according to the present embodiment, it is possible to improve the sealing property when supplying the fluid to the metal pipe material 14.

Further, the molding system 100 according to the present embodiment further includes a holding portion 4 for holding the end portions 14a and 14b of the metal pipe material 14. The control unit 20 is a fluid supply unit so as to expand the end portions 14a, 14b of the metal pipe material 14 by the pressing force of pressing the end portions 14a, 14b of the metal pipe material 14 against the holding portion 40 by the nozzles 7 and 8. 10 is controlled. According to this configuration, the nozzles 7 and 8 and the holding portion 4 can be sealed via the expansion portions 14c and 14d of the metal pipe material 14. Further, when the sealing property is ensured by using such a configuration, the metal pipe material 14 which has been heated and softened is brought into close contact with the tapered concave surfaces 11b and 12b and the tapered surfaces 7b and 8b and pressed. Sufficient sealing performance can be ensured regardless of the state of wear of the tapered concave surfaces 11b and 12b and the tapered surfaces 7b and 8b. Further, in a state where the shapes of the nozzles 7 and 8 are simplified, sufficient sealing performance can be ensured. In addition, the nozzles 7 and 8 can be easily removed after blow molding.

For example, the molding system 200 as shown in FIGS. 5 and 6 may be adopted. In this molding system 200, the control unit (not shown) controls the heating unit 6 so as to heat the ends 14a and 14b of the metal pipe material 14 at least before the fluid is supplied by the fluid supply unit 10. , The fluid supply unit 10 is controlled so that the nozzle 208 expands the end portion 14b of the metal pipe material 14 by the expansion force generated by supplying the fluid to the end portion 14b of the metal pipe material 14. In the molding system 200 according to the modification, the nozzle surrounds the end 14b of the metal pipe material 14 from the outer peripheral side when supplying the fluid, and receives the receiving portion 210 that receives the expanded end 14b of the metal pipe material 14. Have. The receiving portion 210 is formed so as to surround the small diameter portion 209 so as to be separated from the outer peripheral surface of the small diameter portion 209 inserted inside the metal pipe material 14. Further, the control unit controls the fluid supply unit 10 so that the nozzle 208 expands the end portion 14b of the metal pipe material 14 by the expansion force generated by supplying the fluid to the end portion 14b of the metal pipe material 14. As a result, the receiving portion 210 receives the extended end portion 14b of the metal pipe material 14, so that the sealing property is ensured. In this configuration, the expansion process and the fluid supply process are performed at the same time.

As shown in FIG. 6A, when supplying the fluid, the small diameter portion 209 of the nozzle 208 is inserted into the metal pipe material 14. At this time, the nozzle 208 is inserted until the tip surface 210c of the receiving portion 210 comes into contact with the end surface 212a of the electrode 212. At this time, the end portion 14b of the metal pipe material 14 and the bottom surface 210b of the receiving portion 210 are separated so as not to interfere with each other. Further, in this state, the receiving surface 210a (receiving surface) of the receiving portion 210 is separated from the outer peripheral surface of the metal pipe material 14. Next, as shown in FIG. 6B, when the nozzle 208 supplies the fluid to the metal pipe material 14, the vicinity of the end 14b of the metal pipe material 14 expands due to the expansion force, and the receiving surface 210a of the receiving portion 210 expands. Contact. As a result, the expanding portion 14d of the metal pipe material 14 and the receiving surface 210a of the receiving portion 21 are brought into close contact with each other to ensure the sealing property. Further, according to such a structure, it is possible to naturally follow and control the follow-up of the metal pipe material 14 in the axial direction due to blow molding (for example, as in the structure of FIG. 4, the end portion of the metal pipe material 14). The positions near 14a and 14b are not fixed). In addition, the adhesion can be improved by the blow pressure.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

In the above embodiment, the metal pipe material 14 is heated by using the Joule heat generated by energization by providing the heating unit 6 capable of heat treatment between the upper and lower molds, but the present invention is not limited thereto. For example, the molding system is provided with a heating furnace or the like, and the metal pipe after heating in the heating furnace may be carried between the molds. In addition to using Joule heat generated by energization, radiant heat from a heater or the like may be used, or high-frequency induced current may be used for heating. For example, a heater may be arranged in the vicinity of the metal pipe material 14 and heating may be performed before closing the mold. At this time, it is sufficient that at least the ends 14a and 14b of the metal pipe material 14 can be heated.

Further, in the above embodiment, the fluid supplied by the nozzles 7 and 8 is a liquid such as water or oil, but a gas such as compressed air or an inert gas may be supplied.

1 ... Blow molding mold (mold), 2 ... Lower mold (mold), 3 ... Upper mold (mold), 4 ... Holding part, 6 ... Heating part, 7, 8 ... Nozzle, 10 ... Fluid supply part , 14 ... Metal pipe material, 20 ... Control unit, 80 ... Metal pipe, 100, 200 ... Molding system.

Claims (3)

A molding system that expands and molds a metal pipe in a mold.
With the metal pipe material placed in the mold, at least the heating part that heats the end of the metal pipe material, and
A nozzle that supplies fluid from the end of the metal pipe material to the inside is provided.
The heating portion heats the end portion of the metal pipe material in a state of being arranged on the outer peripheral side of the end portion of the metal pipe material.
A molding system in which the nozzle is arranged on the inner peripheral side of the metal pipe material and expands the end of the metal pipe material by a pressing force when pressed against the end of the metal pipe material. The heating part is
It supplies electric power to the metal pipe material to heat the metal pipe material.
It has an electrode in contact with the end of the metal pipe material and has
The electrodes are arranged on the outside of the mold and
The electrode holds the metal pipe material as the nozzle is pressed against the end of the metal pipe material.
The molding system according to claim 1. The nozzle has a first tapered surface so as to taper toward the tip.
The electrode is
It is provided on the outside of the mold and
A second tapered surface parallel to the first tapered surface is provided on the side surface on the side away from the mold.
The nozzle presses the end portion of the metal pipe material against the second tapered surface by the first tapered surface to expand the end portion of the metal pipe material.
The molding system according to claim 2.

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