Forming device and metal tube

Abstract

A forming apparatus for forming a flanged metal tube, the forming apparatus having a forming die for forming the metal tube, wherein, in cross-section, the forming die has a first die and a second die facing each other in a first direction, and also has a third die for restricting a flanged portion of the metal tube material, the third die continuously correcting the offset of the flanged portion until the first die and the second die are closed.

Description

Technical Field

[0001] This invention relates to a forming apparatus and a metal tube. Background Technology

[0002] Previously, a forming apparatus for forming metal tubes was known. For example, Patent Document 1 disclosed a forming apparatus comprising: a forming mold having a lower mold and an upper mold paired with each other; and a fluid supply unit for supplying fluid into a metal tube material held between the forming molds.

[0003] Previous technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2009-220141 Summary of the Invention

[0006] The technical problem to be solved by the invention

[0007] In the aforementioned conventional forming apparatus, a flanged metal tube is sometimes formed by flattening both sides of the metal tube material in the width direction using an upper and lower mold. However, this forming apparatus has the following problem: it is impossible to restrict the expansion of the flange portion in the width direction, making it difficult to form the flange portion into the desired size.

[0008] This invention was made to solve this problem. The object of this invention is to provide a forming apparatus that can reduce the size deviation of the flange portion and a metal tube that reduces the size deviation of the flange portion.

[0009] means for solving technical problems

[0010] An embodiment of the present invention relates to a molding apparatus for forming a flanged metal tube. The molding apparatus includes a molding die for forming the metal tube. In cross-section, the molding die has a first die and a second die facing each other in a first direction, and also has a third die for restricting the flange pre-determined portion of the metal tube material. The third die continuously corrects the offset of the flange pre-determined portion until the first die and the second die are closed.

[0011] In the molding apparatus, when viewed in cross-section, the molding die includes a first die and a second die facing each other in a first direction. Furthermore, the molding die also includes a third die for restricting the flange pre-formed portion of the metal tube. This third die continuously corrects the misalignment of the flange pre-formed portion until the first die and the second die are closed. Therefore, even during the middle of the process where the first die and the second die are closing and flattening the flange pre-formed portion, the third die can continuously correct the misalignment of the flange pre-formed portion. This reduces the possibility of size deviations in the flange portion after molding.

[0012] The third mold is disposed on at least one side of the metal tube material in a second direction intersecting the first direction. The third mold is configured such that as the first and second molds approach each other, the second mold moves away from the metal tube material. This third mold can limit the excessive expansion of the flange portion flattened by the first and second molds in the metal tube material towards the second direction. Here, the third mold is configured such that as the first and second molds approach each other, the third mold moves away from the metal tube material. Therefore, even in the middle of the process where the first and second molds are closing and flattening the flange portion, the flange portion can be continuously restrained. This reduces the possibility of size deviation in the flange portion.

[0013] By forming a conical structure between the third mold and the first mold, and at least one conical structure between the third mold and the second mold, the third mold moves away from the metal tube material as the first mold and the second mold move closer to each other. In this way, the third mold can be moved away from the metal tube material using a simple structure.

[0014] The forming die can form a bent metal tube when viewed from the first direction. In this case, the size of the flange is prone to deviation on the inner and outer circumferential sides of the bend. However, by adopting the structure of the present invention, this deviation can be reduced.

[0015] The metal tube has flanges on both sides in a second direction that intersects the first direction, and the forming die may have a pair of third dies disposed on both sides of the metal tube material in the second direction. In this case, the size deviation of the flanges on both sides of the metal tube can be reduced.

[0016] A pair of third molds can be configured such that the flange portions on both sides are the same size in the second direction. In this case, the flange portions on both sides of the metal tube can be made to be the same size.

[0017] A pair of third molds can be configured such that the flange portions on both sides are of different predetermined sizes in the second direction. In this case, the flange portions on both sides of the metal tube can be set to the desired size.

[0018] The forming apparatus may also include a fluid supply unit for supplying fluid to the heated metal tube material. In the heated metal tube material, the size of the flange is prone to deviation due to temperature variations, etc. However, by employing the structure of the present invention, this deviation can be reduced.

[0019] The molding apparatus may also have an elastic mechanism that applies a spring force to the metal tube material side of the third mold in the second direction, which intersects with the first direction. In this case, the third mold can return to its original position when the first and second molds are opened, without the need for expensive actuators or the like.

[0020] One embodiment of the present invention relates to a metal tube having a hollow tube portion and a pair of flange portions protruding from the tube portion toward both sides in the width direction, wherein the size of the pair of flange portions in the width direction is a predetermined size that is different from each other.

[0021] In a metal tube, a pair of flanges have different specified sizes in the width direction. By performing a process during molding to ensure each flange is the specified size, deviations in flange size can be reduced.

[0022] An embodiment of the present invention relates to a molding apparatus for forming a flanged metal tube. The molding apparatus includes a molding die for forming the metal tube. In cross-section, the molding die has a first die and a second die facing each other in a first direction, and also has a third die disposed on at least one side of the metal tube material in a second direction intersecting the first direction. The third die is configured such that as the first die and the second die move closer to each other, the third die moves away from the metal tube material.

[0023] In the forming apparatus, when viewed in cross-section, the forming mold has a first mold and a second mold facing each other in a first direction. Furthermore, the forming mold also has a third mold disposed on at least one side of the metal tube material in a second direction intersecting the first direction. This third mold can prevent the flange portion in the metal tube material, flattened by the first and second molds, from excessively expanding in the second direction. Here, the third mold is configured such that as the first and second molds approach each other, the third mold moves away from the metal tube material. Therefore, even in the middle of the process where the first and second molds are closing and flattening the flange portion, the third mold can continuously restrain the flange portion. This reduces the possibility of size deviations in the flange portion.

[0024] Invention Effects

[0025] According to the present invention, a forming apparatus capable of reducing the size deviation of the flange portion and a metal tube that reduces the size deviation of the flange portion are provided. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a molding apparatus according to an embodiment of the present invention.

[0027] Figure 2 It is a cross-sectional view showing the state when the nozzle seals the metal tube material.

[0028] Figure 3 It is a cross-sectional view showing the state of forming based on a molding die.

[0029] Figure 4 It is a cross-sectional view showing the state of forming based on a molding die.

[0030] Figure 5It is a cross-sectional view showing the state of forming based on a molding die.

[0031] Figure 6 It is a cross-sectional view showing the state of forming based on a molding die.

[0032] Figure 7 It is a cross-sectional view showing the state of forming based on a molding die.

[0033] Figure 8 It is a cross-sectional view showing the state of forming based on a molding die.

[0034] Figure 9 This is a schematic diagram showing the metal tube material and the bending state of the metal tube. Detailed Implementation

[0035] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, in the drawings, the same or equivalent parts are labeled with the same symbols, and repeated descriptions are omitted.

[0036] Figure 1 This is a schematic diagram of the molding apparatus 1 according to this embodiment. Figure 1 As shown, the forming apparatus 1 is an apparatus for forming a hollow metal tube by blow molding. In this embodiment, the forming apparatus 1 is provided on a horizontal plane. The forming apparatus 1 includes a forming mold 2 (forming die), a drive mechanism 3, a holding part 4, a heating part 5, a fluid supply part 6, a cooling part 7, and a control part 8. In this specification, the metal tube refers to the hollow article after forming by the forming apparatus 1, and the metal tube material 40 refers to the hollow article before forming by the forming apparatus 1. The metal tube material 40 is a tube material of hardenable steel. Furthermore, the extension direction of the metal tube material 40 during forming in the horizontal direction is sometimes referred to as the "length direction", and the direction orthogonal to the length direction is referred to as the "width direction (second direction)".

[0037] The forming mold 2 is a mold for forming the metal tube material 40 into a metal tube. It includes a lower mold 11 (first mold) and an upper mold 12 (second mold) facing each other in the vertical direction (first direction). Furthermore, the forming mold 2 also includes a pair of transverse side molds 14 and 15 (third mold) facing each other in the width direction (see reference). Figure 3 The detailed shapes of molds 11, 12, 14, and 15 will be described later. The lower mold 11 and the upper mold 12 are made of steel blocks. The lower mold 11 is fixed to the base 13 via a mold base or the like. The upper mold 12 is fixed to the sliding member of the drive mechanism 3 via a mold base or the like.

[0038] The drive mechanism 3 is a mechanism that moves at least one of the lower mold 11 and the upper mold 12. Figure 1In this design, the drive mechanism 3 has a structure that moves only the upper mold 12. The drive mechanism 3 includes: a sliding member 21 that moves the upper mold 12 toward the lower mold 11 and the direction in which the upper mold 12 closes with each other; a pull-back cylinder 22 that acts as a brake and generates a force that pulls the sliding member 21 upward; a main cylinder 23 that acts as a drive source and lowers the sliding member 21 and applies pressure; and a drive source 24 that imparts a driving force to the main cylinder 23.

[0039] The holding part 4 is a mechanism for holding the metal tube material 40 disposed between the lower mold 11 and the upper mold 12. The holding part 4 includes a lower electrode 26 and an upper electrode 27 that hold the metal tube material 40 at one end along the length of the forming mold 2, and a lower electrode 26 and an upper electrode 27 that hold the metal tube material 40 at the other end along the length of the forming mold 2. The lower electrode 26 and the upper electrode 27 on both sides along the length clamp the metal tube material 40 near its end from the vertical direction, thereby holding the metal tube material 40. Furthermore, grooves with shapes corresponding to the outer peripheral surface shape of the metal tube material 40 are formed on the upper surface of the lower electrode 26 and the lower surface of the upper electrode 27. A drive mechanism (not shown) is provided on the lower electrode 26 and the upper electrode 27, so that the lower electrode 26 and the upper electrode 27 can move independently in the vertical direction.

[0040] The heating unit 5 heats the metal tube material 40. The heating unit 5 is a mechanism that heats the metal tube material 40 by energizing it. The heating unit 5 heats the metal tube material 40 when it is between the lower mold 11 and the upper mold 12, and when the metal tube material 40 is separated from both molds 11 and 12. The heating unit 5 includes: lower electrodes 26 and upper electrodes 27 on both sides along its length; and a power supply 28 that allows current to flow through these electrodes 26 and 27 to the metal tube material. Alternatively, the heating unit 5 can be configured in a preceding process of the molding apparatus 1 for external heating.

[0041] The fluid supply unit 6 is a mechanism for supplying high-pressure fluid into the metal tube material 40 held between the lower mold 11 and the upper mold 12. The fluid supply unit 6 supplies high-pressure fluid to the metal tube material 40, which has been heated to a high temperature by the heating unit 5, to cause the metal tube material 40 to expand. The fluid supply unit 6 is provided at both ends along the length of the molding die 2. The fluid supply unit 6 includes: a nozzle 31 for supplying fluid into the metal tube material 40 from an opening at one end; a drive mechanism 32 for moving the nozzle 31 forward and backward relative to the opening of the metal tube material 40; and a supply source 33 for supplying high-pressure fluid into the metal tube material 40 via the nozzle 31. The drive mechanism 32 keeps the nozzle 31 in close contact with the end of the metal tube material 40 (see reference) during fluid supply and during venting to ensure a tight seal. Figure 2 At other times, the nozzle 31 is separated from the end of the metal tube material 40. Additionally, the fluid supply unit 6 can supply high-pressure air or inert gas as the fluid. Furthermore, the fluid supply unit 6 can be integrated with the holding unit 4, which has a mechanism for moving the metal tube material 40 in the up-and-down direction, and the heating unit 5, which are part of the same device.

[0042] Figure 2 This is a cross-sectional view showing the state when nozzle 31 seals the metal tube material 40. (Example) Figure 2 As shown, the nozzle 31 is a cylindrical component into which the end of the metal tube material 40 can be inserted. The nozzle 31 is supported on the drive mechanism 32 such that its centerline aligns with the reference line SL1. The inner diameter of the supply port 31a at the end of the nozzle 31 on the metal tube material 40 side is approximately the same as the outer diameter of the expanded metal tube material 40. In this state, the nozzle 31 supplies high-pressure fluid to the metal tube material 40 from the internal flow path 36. Furthermore, an example of a high-pressure fluid could be gas.

[0043] Return to Figure 1 The cooling section 7 is a mechanism for cooling the molding die 2. By cooling the molding die 2, the cooling section 7 can quickly cool the expanded metal tube material 40 when it comes into contact with the molding surface of the molding die 2. The cooling section 7 includes a flow path 36 formed inside the lower die 11 and the upper die 12, and a water circulation mechanism 37 that supplies cooling water to the flow path 36 and circulates it.

[0044] The control unit 8 is a device for controlling the entire molding apparatus 1. The control unit 8 controls the drive mechanism 3, the holding unit 4, the heating unit 5, the fluid supply unit 6, and the cooling unit 7. The control unit 8 repeatedly performs the action of molding the metal tube material 40 with the molding die 2.

[0045] Specifically, the control unit 8, for example, controls the timing of transport by a robotic arm or other transport device to place the metal tube material 40 between the open lower mold 11 and upper mold 12. Alternatively, the control unit 8 may wait for the operator to manually place the metal tube material 40 between the lower mold 11 and upper mold 12. Furthermore, the control unit 8 controls the actuator of the holding unit 4, etc., so that the metal tube material 40 is supported by the lower electrodes 26 on both sides in the longitudinal direction, and then the upper electrode 27 is lowered to clamp the metal tube material 40. The control unit 8 also controls the heating unit 5 to electrically heat the metal tube material 40. As a result, current flows axially through the metal tube material 40, and due to the resistance of the metal tube material 40 itself, the metal tube material 40 heats up based on Joule heating.

[0046] The control unit 8 controls the drive mechanism 3 to lower the upper mold 12 closer to the lower mold 11, thereby closing the molding die 2. Simultaneously, the control unit 8 controls the fluid supply unit 6 to seal the openings at both ends of the metal tube material 40 using nozzles 31 and supply fluid. As a result, the softened metal tube material 40 expands and contacts the molding surface of the molding die 2. Furthermore, the metal tube material 40 is molded to the same shape as the molding surface of the molding die 2. When the metal tube material 40 contacts the molding surface, the molding die 2, cooled by the cooling unit 7, rapidly cools the metal tube material 40, thereby quenching the metal tube material 40.

[0047] Next, refer to Figure 3 and Figure 4 The detailed structure of the molding die 2 of the molding device 1 will be described. First, refer to... Figure 4 Section (b) describes the metal tube 41 formed by the forming mold 2. The metal tube 41 has a hollow tube portion 41a and flange portions 41b and 41c protruding to both sides in the width direction. The tube portion 41a has a rectangular tube shape. However, the shape of the tube portion 41a is not particularly limited and can be formed into any shape depending on the application. The flange portions 41b and 41c are formed by flattening the two ends of the metal tube material 40 in the width direction using molds 11 and 12. In addition, the portions of the metal tube material 40 that will become flange portions 41b and 41c after forming are called flange pre-formed portions 40b and 40c. Figure 4 (a) In the following description, unless otherwise specified, the protrusion in the formed metal tube 41 is referred to as the "flange portion". Furthermore, the portion of the metal tube material 40 in its pre-forming state that will become the flange portion after forming is referred to as the "flange pre-formation portion". The shape of the "flange pre-formation portion" changes according to the progress of forming. And, as... Figure 9 As shown in (a), when viewed from above, the metal tube 41 is bent in a manner that protrudes towards one side in the width direction. Figure 9In the example shown in (a), flange 41b is disposed on the inner peripheral side and flange 41c is disposed on the outer peripheral side.

[0048] like Figure 3 As shown in (a), the lower mold 11 includes a flat portion 51 extending in the width direction, a recess 52 formed at the center of the flat portion 51 in the width direction, and support portions 53 and 54 formed at two outer ends in the width direction. The recess 52 is the portion from which the lower part of the tube portion 41a of the metal tube 41 is formed (see reference). Figure 4 (b)). The two sides of the recess 52 in the width direction of the planar portion 51 are configured as forming surfaces for forming the flange portions 41b and 41c (see reference). Figure 4 (b)). Support portions 53 and 54 are portions that protrude upward from the planar portion 51. Support portion 53 supports the transverse mold 14, and support portion 54 supports the transverse mold 15.

[0049] The upper mold 12 includes a flat portion 61 extending in the width direction and a molding body portion 62 protruding downward from the center of the flat portion 61 in the width direction. The molding body portion 62 has a generally trapezoidal cross-sectional shape that tapers downward. A recess 63 is provided on the lower surface 62a of the molding body portion 62. The recess 63 is the portion from which the upper part of the tube portion 41a of the metal tube 41 is formed (see reference). Figure 4 (b)). The lower surface 62a of the molded main body 62 is configured on both sides of the recess 63 in the width direction as molding surfaces for molding the flange portions 41b and 41c (see reference). Figure 4 (b)). The molded main body 62 has tapered surfaces 62b and 62c that extend outward in the width direction from the lower surface 62a toward the upper planar portion 61.

[0050] A transverse mold 14 is disposed on one side of the metal tube material 40 in the width direction. A transverse mold 15 is disposed on the other side of the metal tube material 40 in the width direction. Molds 14 and 15 are molds that restrict the expansion of the flange pre-formed portions 40b and 40c of the metal tube material 40 when they expand outward in the width direction. Molds 14 and 15 have limiting surfaces 14a and 15a on their inner sides in the width direction to restrict the expansion of the flange pre-formed portions 40b and 40c. Tapered surfaces 14b and 15b are formed on the upper side of the limiting surfaces 14a and 15a, which are inclined in a manner that expands outward in the width direction as they move upward.

[0051] Mold 14 is connected to a gas damper 66 (elastic mechanism) provided in the support portion 53 of mold 11. The gas damper 66 extends from the support portion 53 toward the inward side in the width direction and is connected to mold 14. Mold 15 is connected to a gas damper 67 (elastic mechanism) provided in the support portion 54 of mold 11. The gas damper 67 extends from the support portion 54 toward the inward side in the width direction and is connected to mold 15. Gas dampers 66 and 67 are elastic mechanisms that apply elastic force to the metal tube material 40 side (i.e., the inward side) of molds 14 and 15 in the width direction.

[0052] Here, molds 14 and 15 are configured such that as the lower mold 11 and the upper mold 12 approach each other, molds 14 and 15 move away from the metal tube material 40. In this embodiment, as the upper mold 12 descends, molds 14 and 15 move outward in the width direction. Specifically, through the conical structures 71 and 72 formed between molds 14 and 15 and the upper mold 12, molds 14 and 15 move outward in the width direction in such a way that as molds 11 and 12 approach each other, molds 14 and 15 move away from the metal tube material 40.

[0053] Next, the molding process based on molding die 2 will be explained. For example... Figure 3 As shown in (a), in the initial molding state, each mold 11, 12, 14, and 15 is positioned separately from the metal tube material 40. Here, in this embodiment, molds 14 and 15 are positioned such that the flanges 41b and 41c on both sides (see reference) Figure 4 In section (b) the molds are arranged in a manner where they are the same size in the width direction. Specifically, molds 14 and 15 are arranged symmetrically to the center position in the width direction of the forming mold 2. As a result, the inner limiting surfaces 14a and 15a of molds 14 and 15 in the width direction are arranged at the same distance from the center position in the width direction of the forming mold 2. In this state, the control unit 8 heats the metal tube material 40.

[0054] Next, as Figure 3As shown in (b), the control unit 8 lowers the mold 12 downwards. Here, the mold 12 descends to a position where the conical surfaces 62b and 62c of the mold 12 contact the conical surfaces 14b and 15b of the molds 14 and 15. The control unit 8 then controls the fluid supply unit 6 to supply fluid into the metal tube material 40, thereby performing blow molding (one-time blow molding). Parts of the flange pre-determined portions 40b and 40c on both sides of the metal tube material 40 in the width direction expand and enter between the flat portion 51 of the mold 11 and the lower surface 62a of the mold 12. At this time, the flange pre-determined portions 40b and 40c contact the limiting surfaces 14a and 15a of the molds 14 and 15, thereby limiting their further deformation outwards in the width direction. Thus, with the molds 14 and 15 limiting the flange pre-determined portions 40b and 40c using the limiting surfaces 14a and 15a, the offset of the flange pre-determined portions 40b and 40c can be corrected.

[0055] Next, as Figure 4 As shown in (a), the control unit 8 further lowers the mold 12 downwards. At this time, the conical surfaces 62b and 62c of the mold 12 also move downwards. As a result, the conical surfaces 14b and 15b of the molds 14 and 15 are guided by the conical surfaces 62b and 62c of the mold 12 and move outwards in the width direction. Therefore, the limiting surfaces 14a and 15a of the molds 14 and 15 also move outwards in the width direction. In addition, based on the elastic force of the gas dampers 66 and 67, the molds 14 and 15 maintain the state of being pressed against the conical surfaces 62b and 62c of the mold 12.

[0056] On the other hand, the flange pre-protrusion portions 40b and 40c of the metal tube material 40 are further flattened between the flat portion 51 of the mold 11 and the lower surface 62a of the mold 12, thereby gradually increasing their width dimension as the mold 12 descends. However, even if the flange pre-protrusion portions 40b and 40c are to protrude significantly outward in the width direction due to deviation, they will be restricted by the limiting surfaces 14a and 15a of the molds 14 and 15, and thus will not increase further. Thus, even if the molds 14 and 15 are not in contact with the flange pre-protrusion portions 40b and 40c, the state in which the flange pre-protrusion portions 40b and 40c (the flange pre-protrusion portions 40b and 40c that are to protrude significantly) are restricted by the limiting surfaces 14a and 15a can be said to be a state of correcting the deviation of the flange pre-protrusion portions 40b and 40c.

[0057] The control unit 8 further lowers the mold 12 downwards, making it as follows: Figure 4The molds 11 and 12 shown in (b) are in a fully closed state (bottom dead center). At this time, the flange pre-formed portions 40b and 40c are completely flattened. After the flange portions 41b and 41c are formed, the control unit 8 supplies fluid to the metal tube material 40 through the fluid supply unit 6, thereby forming the tube portion 41a corresponding to the shape of the recesses 52 and 63, thus completing the metal tube 41. Afterwards, if the control unit 8 moves the mold 12 upward to open the mold, the molds 14 and 15 return to their original position due to the restoring force of the gas dampers 66 and 67. Figure 3 Position (a) is shown. Here, the fully closed state of molds 11 and 12 corresponds to the mold closing state of molds 11 and 12. Molds 14 and 15 continuously correct the offset of the flange pre-positioned portions 40b and 40c until the mold is closed.

[0058] Next, the effects of the molding apparatus 1 according to this embodiment will be explained.

[0059] In the molding apparatus 1, when viewed in cross-section, the molding die 2 has dies 11 and 12 facing each other in the vertical direction (first direction). Furthermore, the molding die 2 also has dies 14 and 15 disposed on both sides of the metal tube material 40 in the width direction (second direction) intersecting the vertical direction. These dies 14 and 15 can prevent the flange pre-formed portions 40b and 40c flattened by the dies 11 and 12 in the metal tube material 40 from excessively expanding in the width direction. Here, the dies 14 and 15 are configured such that as the dies 11 and 12 move closer to each other, the dies 14 and 15 move further away from the metal tube material 40. Therefore, even during the middle of the mold closing operation of the dies 11 and 12, which flattens the flange pre-formed portions 40b and 40c, the dies 14 and 15 can continuously restrict the flange pre-formed portions 40b and 40c. This reduces the possibility of size deviations in the flange portions 41b and 41c after molding.

[0060] By forming conical structures 71 and 72 between molds 14 and 15 and the upper mold 12, as molds 11 and 12 move closer to each other, molds 14 and 15 move away from the metal tube material 40. At this time, molds 14 and 15 can be moved away from the metal tube material 40 by simply setting conical structures 71 and 72.

[0061] The metal tube 41 has flanges 41b and 41c on both sides in the width direction, and the forming mold 2 has a pair of molds 14 and 15 arranged on both sides of the metal tube material 40 in the width direction. At this time, the size deviation of the flanges 41b and 41c on both sides of the metal tube 41 can be reduced.

[0062] The molding apparatus 1 also includes gas dampers 66 and 67 that apply elastic force to the metal tube material 40 side of the molds 14 and 15 in the width direction. At this time, the molds 14 and 15 can return to their original positions when the molds 11 and 12 are opened without the need for expensive actuators.

[0063] A pair of molds 14 and 15 are configured such that the flange portions 41b and 41c on both sides are the same size in the width direction. At this time, it is possible to make the flange portions 41b and 41c on both sides of the metal tube 41 the same size.

[0064] The forming mold 2 forms a bent metal tube 41 when viewed from above. At this time, the size of the flanges 41b and 41c is prone to deviation on the inner and outer circumferential sides of the bend. However, by adopting the structure of this embodiment, this deviation can be reduced.

[0065] The forming apparatus 1 also includes a fluid supply unit 6 for supplying fluid to the heated metal tube material 40. In the heated metal tube material 40, the size of the flange portions 41b and 41c is prone to deviation due to temperature deviations, etc. However, by adopting the structure of this embodiment, this deviation can be reduced.

[0066] Next, the relationship between the bending of the metal tube 41 (metal tube material 40) and temperature will be explained in more detail. For example... Figure 9 As shown in (a), if the metal tube material 40 is heated by an electric current, the current density on the inner circumference will be higher than that on the outer circumference, thus the inner circumference will become hotter, resulting in a heating temperature difference. Consequently, the thermal expansion on the inner circumference of the metal tube material 40 will be greater than that on the outer circumference. Furthermore, as... Figure 9 As shown in (b), if molds 11 and 12 are closed to form flanges 41b and 41c, compressive force will act on the inner circumferential side, and tensile force will act on the outer circumferential side. Consequently, the flange 41b on the inner circumferential side will become excessively thick. Therefore, as... Figure 9 As shown in (c), due to the difference between the amount of expansion and contraction along the length and the amount of thermal expansion, the metal tube 41 will deform with a smaller bending angle, causing the tube center to easily shift towards the outer periphery. Therefore, without the molds 14 and 15 as in this embodiment, the size of the flange portion 41b on the inner periphery tends to increase in the width direction. In contrast, the forming apparatus 1 according to this embodiment can reduce the deviation of the flange portions 41b and 41c by means of the molds 14 and 15, thus making the size of the flange portion 41b on the inner periphery equal to the size of the flange portion 41c on the outer periphery. Furthermore, by appropriately adjusting the operation of the molds 14 and 15, the forming freedom of the angle R of the complex-shaped metal tube 41 can be increased.

[0067] In the molding apparatus 1, molds 14 and 15 continuously correct the offset of the flange pre-formed portions 40b and 40c until molds 11 and 12 are closed. Therefore, even when molds 11 and 12 are in the middle of the mold-closing operation, thus flattening the flange pre-formed portions 40b and 40c, molds 14 and 15 can continuously correct the offset of the flange pre-formed portions 40b and 40c. As a result, the size deviation of the flange portions 41b and 41c after molding can be reduced.

[0068] The present invention is not limited to the embodiments described above.

[0069] For example, in the above embodiment, the molds 14 and 15 are configured such that the size of the flange portion 41b in the width direction is the same as the size of the flange portion 41c in the width direction. Alternatively, the pair of molds 14 and 15 may also be configured such that the flange portions 41b and 41c on both sides are each a predetermined size that is different from each other in the width direction. In this case, the flange portions 41b and 41c on both sides of the metal tube 41 can be set to the desired size.

[0070] For example, such as Figure 6 As shown in (b), the flange portion 41b can be formed to be larger than the flange portion 41c. In this case, as... Figure 5 As shown in (a), in the initial state, the limiting surface 14a of the mold 14 only needs to be positioned at a position further outward than the limiting surface 15a of the mold 15 in the central position relative to the width direction of the forming mold 2. At this time, as... Figure 5 As shown in (b), during one blow molding stage, the flange pre-formed portion 40c is in contact with the limiting surface 15a, while the flange pre-formed portion 40b is separated from the limiting surface 14a. Therefore, the flange pre-formed portion 40c expands while being limited by the limiting surface 15a, while the flange pre-formed portion 40b can expand without restriction. Figure 6 As shown in (a), if the control unit 8 further moves the mold 12 downwards, the mold 15 moves outwards while the mold 14 remains stationary until it contacts the tapered surface 62b. On the other hand, the flange pre-determined portion 40b is flattened and expands outwards, thereby contacting the limiting surface 14a. Thus, the flange pre-determined portion 40b is limited by the limiting surface 14a. If the control unit 8 further moves the mold 12 downwards, as... Figure 6 The flanges 41b and 41c are shown in (b).

[0071] As mentioned above, Figure 6 The metal tube 41 shown in (b) has a hollow tube portion 41a and a pair of flange portions 41b and 41c protruding from the tube portion 41a toward both sides in the width direction, and the size of the pair of flange portions 41b and 41c in the width direction is a predetermined size that is different from each other.

[0072] In the metal tube 41, a pair of flange portions 41b and 41c have different sizes in the width direction. At this time, if a process is performed during molding to make each flange portion 41b and 41c the specified size, then the size deviation of the flange portions 41b and 41c can be reduced.

[0073] Furthermore, in Figures 5-6 In the manner shown, molds 14 and 15 are closed until molds 11 and 12 are joined. Figure 6 During the period up to (b), the offset of the flange pre-determined portions 40b and 40c is also continuously corrected.

[0074] In the above embodiment, the metal tube 41 has a pair of flanges 41b and 41c. Alternatively, the metal tube 41 may also have a flange only on one side in the width direction. For example, as Figure 8 As shown in (b), the metal tube 41 may have only one flange portion 41b. In this case, as... Figure 7 As shown in (a), in the initial state, the limiting surface 14a of the mold 14 is positioned at a location further outward than the limiting surface 15a of the mold 15 in the central position relative to the width direction of the forming mold 2. Furthermore, the recesses 52 and 63 are formed further to the right than the central position. At this time, the limiting surface 15a is positioned at the right end of the recesses 52 and 63. At this time, as... Figure 7 As shown in (b), during one blow molding stage, the flange pre-formed portion 40b contacts the limiting surface 14a, while the right end of the tube portion 40a contacts the limiting surface 15a. Therefore, no flange pre-formed portion is formed on the right side. Figure 8 As shown in (a), if the control unit 8 further moves the mold 12 downwards, the molds 14 and 15 move outwards. The flange pre-formation remains unformed on the right side of the tube portion 40a. If the control unit 8 further moves the mold 12 downwards, then as shown in (a), the molds 14 and 15 move outwards. Figure 8 The flange portion 41b is shown in (b).

[0075] Furthermore, in Figures 7-8 In the manner shown, mold 14 is in place until molds 11 and 12 are closed ( Figure 8 The offset of the flange pre-determined portion 40b is continuously corrected up to the period up to (b).

[0076] In addition, in the above embodiment, the limiting mold is provided on both sides in the width direction, but the limiting mold may be provided only on one side in the width direction.

[0077] In the above embodiment, the conical structures 71 and 72 are formed between the molds 14 and 15 and the upper mold 12. Alternatively, the conical structures can also be formed between the molds 14 and 15 and the lower mold 11, or between the molds 14 and 15 and the molds 11 and 12.

[0078] In the above embodiment, a gas damper is used as the elastic mechanism. However, the elastic mechanism can be any mechanism that generates elastic force, and can also be composed of elastic components or the like. Furthermore, the molds 14 and 15 can also be structured so that their position in the width direction can be controlled by an actuator or the like.

[0079] Furthermore, in the above embodiments, the mold used in the STAF molding apparatus was described as an example. However, the type of molding apparatus using the mold involved in this invention is not particularly limited, as long as it is a molding apparatus that supplies fluid to cause the metal tube material to expand.

[0080] Symbol Explanation

[0081] 1-Forming device, 2-Forming mold (forming die), 6-Fluid supply unit, 11-Mold (first mold), 12-Mold (second mold), 14, 15-Mold (third mold), 40-Metal tube material, 40b, 40c-Flange pre-positioning part, 41b, 41c-Flange part, 41-Metal tube, 66, 67-Gas damper (elastic mechanism), 71, 72-Conical structure.

Claims

1. A forming apparatus for forming a flanged metal tube, characterized in that, The forming device includes a forming mold for forming the metal tube. In cross-section, the forming mold has a first mold and a second mold facing each other in a first direction, and also has a third mold for restricting the flange pre-determined portion of the metal tube material. The third mold continuously corrects the offset of the flange predetermined portion until the first mold and the second mold are joined together. By forming at least one tapered structure between the third mold and the first mold, and between the third mold and the second mold, as the first mold and the second mold move closer to each other, the third mold moves away from the metal tube material. The third mold has a limiting surface, which can continuously limit the offset of the flange pre-determined portion.

2. The molding apparatus according to claim 1, characterized in that, The third mold is disposed on at least one side of the metal tube material in a second direction intersecting the first direction. The third mold is configured such that as the first mold and the second mold move closer to each other, the third mold moves away from the metal tube material.

3. The molding apparatus according to claim 1 or 2, characterized in that, The molding die forms the metal tube that is bent when viewed from the first direction.

4. The molding apparatus according to claim 1, characterized in that, The metal tube has flanges on both sides in a second direction that intersects with the first direction. The forming mold has a pair of third molds disposed on both sides of the metal tube material in the second direction.

5. The molding apparatus according to claim 4, characterized in that, The pair of third modules are configured such that the flange portions on both sides are the same size in the second direction.

6. The molding apparatus according to claim 4, characterized in that, The pair of third modules are configured such that the flange portions on both sides are of different sizes in the second direction.

7. The molding apparatus according to claim 1, characterized in that, It also includes a fluid supply unit for supplying fluid to the heated metal tube material.

8. The molding apparatus according to claim 1, characterized in that, It also has an elastic mechanism that applies elastic force to the metal tube material side of the third mold in a second direction that intersects with the first direction.

9. A forming apparatus for forming a flanged metal tube, characterized in that, The forming device includes a forming mold for forming the metal tube. In cross-section, the forming mold has a first mold and a second mold facing each other in a first direction, and also has a third mold disposed on at least one side of the metal tube material in a second direction intersecting the first direction. The third mold is configured such that, through at least one conical structure formed between the third mold and the first mold, and another conical structure formed between the third mold and the second mold, the third mold moves away from the metal tube material as the first mold and the second mold move closer to each other. The third mold has a limiting surface, which can continuously limit the displacement of the flange pre-determined portion of the metal tube material.

Images