Forming Device

This is a bypass continuation of International PCT Application No. PCT/JP2024/017154, filed on May 8, 2024, which claims priority to Japanese Patent Application No. 2023-085521, filed on May 24, 2023, which are incorporated by reference herein in their entirety.

A certain embodiment of the present disclosure relates to a forming device.

In the related art, an expansion forming device that forms, by expansion, a metal pipe material is known. For example, an expansion forming device disclosed in the related art forms, by expansion, a metal pipe material by heating the metal pipe material, pressing a nozzle against the metal pipe material to perform sealing, and supplying a high-pressure fluid from the nozzle.

According to an embodiment of the present disclosure, there is provided a forming device including: a fluid supply unit that is disposed at an end portion of a metal pipe material and that supplies a fluid into the metal pipe material through an opening of the end portion; and a sealing mechanism that performs sealing against leakage of the fluid from the metal pipe material when the fluid is supplied by the fluid supply unit into the metal pipe material that is heated by a heating unit, in which the sealing mechanism performs the sealing by contact between the metal pipe material and a non-resin material, without applying an axial force to the metal pipe material.

Here, the above-described expansion forming device performs sealing using a resin material and supplies the fluid. However, in a case in which a temperature of the metal pipe material becomes high near a tip end (for example, in a case in which the metal pipe material is heated in a furnace), there is an issue in that the resin material is damaged during sealing.

It is desirable to provide a forming device for an expansion forming device that can perform sealing in a state in which an influence of a high-temperature metal pipe material is suppressed.

The forming device includes the sealing mechanism that performs sealing against the leakage of the fluid from the metal pipe material when the fluid is supplied by the fluid supply unit into the metal pipe material that is heated by the heating unit. Therefore, the fluid supplied from the fluid supply unit into the metal pipe material is prevented from leaking to the outside of the metal pipe material by the sealing of the sealing mechanism. Here, the sealing mechanism performs the sealing by contact between the metal pipe material and the non-resin material, without applying the axial force to the metal pipe material. As a result, it is possible to select a non-resin material having higher heat resistance than a sealing member such as a resin-based O-ring, as a material of the sealing mechanism. As a result, it is possible to perform sealing in a state in which the influence of the high-temperature metal pipe material is suppressed.

The fluid supply unit may be disposed in an inner portion of the metal pipe material, and the sealing mechanism may be disposed in at least one of the inner portion and an outer portion of the metal pipe material, and perform the sealing using a sealing surface moved by the sealing mechanism in a radial direction toward the metal pipe material when the fluid is supplied by the fluid supply unit. In this case, the sealing mechanism can press the sealing surface against the metal pipe material in the radial direction, and thus it is possible to more suppress the leakage of the fluid from the metal pipe material.

The forming device may further include a holding unit for the sealing so that the metal pipe material does not buckle when the fluid is supplied by the fluid supply unit. In a case in which the fluid supply unit is mounted in the metal pipe material, even when the pressing is performed with a certain pressing force, the holding unit can prevent the metal pipe material from moving in a pressing direction of the fluid supply unit. Alternatively, the holding unit can hold the metal pipe material transported from a transport device for the metal pipe material.

Hereinafter, a preferred embodiment of a forming device according to the present disclosure will be described with reference to the accompanying drawings. In the drawings, the same portions or equivalent portions will be denoted by the same reference numerals, and the redundant description thereof will be omitted.

is a schematic configuration view illustrating a forming deviceaccording to the present embodiment. As illustrated in, the forming deviceis a device that forms a metal pipe having a hollow shape by blow forming. In the present embodiment, the forming deviceis installed on a horizontal plane. The forming deviceincludes a forming die, a drive mechanism, a holding unit, a fluid supply unit, a cooling unit, and a control unit. In addition, in the present specification, a metal pipe material(metal material) refers to a hollow article before the completion of forming via the forming device. The metal pipe materialis a steel-type pipe material that can be quenched. Further, in a horizontal direction, a direction in which the metal pipe materialextends during the forming may be referred to as a “longitudinal direction”, and a direction perpendicular to the longitudinal direction may be referred to as a “width direction”.

The forming dieis a die that forms a metal pipe from the metal pipe material, and that includes a lower main die(first main die) and an upper main die(second main die) that face each other in an up-down direction. The lower main dieand the upper main dieare formed of a steel block. Each of the lower main dieand the upper main dieis provided with a recessed portion in which the metal pipe materialis accommodated. In a state in which the lower main dieand the upper main dieare in close contact with each other (die closed state), the respective recessed portions form a space having a target shape in which the metal pipe material is to be formed. Therefore, surfaces of the respective recessed portions are forming surfaces of the forming die. The lower main dieis fixed to a base stagevia a die holder or the like. The upper main dieis fixed to a slide of the drive mechanismvia a die holder or the like.

The drive mechanismis a mechanism that moves at least one of the lower main dieand the upper main die. In, the drive mechanismhas a configuration of moving only the upper main die. The drive mechanismincludes a slidethat moves the upper main dieso that the lower main dieand the upper main dieare joined together, a pull-back cylinderas an actuator that generates a force for pulling the slideupward, a main cylinderas a drive source that downward-pressurizes the slide, and a drive sourcethat applies a driving force to the main cylinder.

The holding unitis a mechanism that holds the metal pipe materialdisposed between the lower main dieand the upper main die. The holding unitincludes a lower electrodeand an upper electrodethat hold the metal pipe materialon one end side in the longitudinal direction of the forming die, and a lower electrodeand an upper electrodethat hold the metal pipe materialon the other end side in the longitudinal direction of the forming die. The lower electrodesand the upper electrodeson both sides in the longitudinal direction hold the metal pipe materialby interposing vicinities of end portions of the metal pipe materialfrom the up-down direction. Upper surfaces of the lower electrodesand lower surfaces of the upper electrodesare formed with groove portions having a shape corresponding to an outer peripheral surface of the metal pipe material. The lower electrodeand the upper electrodecan move in the up-down direction together with the movement of the fluid supply unitin the up-down direction.

The fluid supply unitis a mechanism that supplies a high-pressure fluid into the metal pipe materialheld between the lower main dieand the upper main die. The fluid supply unitsupplies the high-pressure fluid into the metal pipe materialthat is brought into a high-temperature state by being heated in a heating furnace or the like in a stage before the forming device, to expand the metal pipe material. The fluid supply unitis provided on both end sides of the forming diein the longitudinal direction. The fluid supply unitincludes a nozzlethat supplies the fluid from an opening portion of an end portion of the metal pipe materialto an inside of the metal pipe material, a drive mechanismthat moves the nozzleforward and backward with respect to the opening portion of the metal pipe material, and a high-pressure fluid supply sourcethat supplies the high-pressure fluid into the metal pipe materialvia the nozzle. The drive mechanismbrings the nozzleinto close contact with the end portion of the metal pipe materialin a state in which the sealing performance is ensured during the fluid supply and exhaust, and causes the nozzleto be separated from the end portion of the metal pipe materialin other cases. The fluid supply unitmay supply a gas such as high-pressure air and an inert gas, as the fluid. In addition, the fluid supply unitis the same device as the holding unitincluding a mechanism that moves the metal pipe materialin the up-down direction.

Returning to, the cooling unitis a mechanism that cools the forming die. The cooling unitcan rapidly cool the metal pipe materialwhen the expanded metal pipe materialcomes into contact with the forming surface of the forming die, by cooling the forming die. The cooling unitincludes flow pathsformed inside the lower main dieand the upper main dieand a water circulation mechanismthat supplies a cooling water to the flow pathsand causes the cooling water to circulate through the flow paths.

The control unitis a device that controls a part of the forming device. The control unitcontrols the drive mechanism, the holding unit, and the fluid supply unit. The control unitrepeatedly performs the operation of forming the metal pipe materialusing the forming die. In addition, the control unitfor the drive mechanismand the control unitfor the holding unitand the fluid supply unitmay be independent of each other. For example, in a case in which the holding unitand the fluid supply unitare newly added to an existing press device, the control unitindependent of the drive mechanismis provided.

Specifically, the control unitcontrols, for example, a transport timing from a transport device, such as a robot arm, to dispose the metal pipe materialbetween the lower main dieand the upper main diein an open state. Alternatively, a worker may manually dispose the metal pipe materialbetween the lower main dieand the upper main die. Additionally, the control unitcontrols an actuator of the holding unitand the like so that the metal pipe materialis supported by the lower electrodeson both sides in the longitudinal direction, and then the upper electrodesare lowered to interpose the metal pipe material.

The control unitcloses the forming dieby controlling the drive mechanismto lower the upper main dieand bring the upper main diecloser to the lower main die. Meanwhile, the control unitcontrols the fluid supply unitto seal the opening portions of both ends of the metal pipe materialwith the nozzleand supply the fluid. As a result, the metal pipe material, which is softened by the heating, expands and comes into contact with the forming surface of the forming die. Then, the metal pipe materialis formed to follow a shape of the forming surface of the forming die. In addition, in a case in which a metal pipe with a flange is formed, a part of the metal pipe materialis made to enter a gap between the lower main dieand the upper main die, and then die closing is further performed to crush the entering part to form a flange portion. When the metal pipe materialcomes into contact with the forming surface, the metal pipe materialis quenched by being rapidly cooled by using the forming diecooled by the cooling unit.

Hereinafter, a sealing mechanismof the forming deviceaccording to the present embodiment will be described in detail with reference to. The sealing mechanismis a mechanism that seals the metal pipe materialin the forming devicethat is an expansion forming device that forms, by expansion, the metal pipe material.is a perspective view illustrating the nozzle. The sealing mechanismis provided at a tip end of the nozzle. The sealing mechanismprevents the high-pressure fluid supplied from a flow pathfrom leaking from the metal pipe materialwhen the tip end of the nozzleis mounted at the end portion of the metal pipe material.

As illustrated in, the sealing mechanismincludes a nozzle base member, a nozzle member, a clamp mechanism, and a hydraulic cylinder. In addition, in the following description, a direction in which a center line CL of the nozzleextends may be referred to as an axial direction D. In the axial direction D, a side of the metal pipe material, that is, a tip end side may be referred to as “front”, and an opposite side may be referred to as “rear”. In addition, the expression such as “radial direction” or “circumferential direction” may be used with reference to the center line CL.

The nozzle base memberis a base member for supporting various members in the nozzle. The nozzle base memberincludes the flow paththat extends along the center line CL on the center line CL. The nozzle base memberincludes a shaft portionextending in the axial direction Dalong the center line CL and an extension portion(see) that expands to an outer peripheral side in the radial direction on the rear side of the shaft portion.

The nozzle memberis a member disposed in an inner portion of the metal pipe materialwhen a gas is supplied to the metal pipe material. The nozzle memberis provided on the front side of the shaft portionof the nozzle base member. A metal O-ringis provided between the nozzle memberand the shaft portion. The metal O-ringcan also prevent damage due to heat even in a case in which the heated metal pipe materialand the nozzle membercome into contact with each other. The nozzle memberhas a cylindrical shape. The flow pathis formed on the center line CL of the nozzle member. The flow pathis open at a front end surfaceof the nozzle member. Therefore, the fluid is supplied from the front end surfaceof the nozzle memberinto the metal pipe material. An outer peripheral surfaceof the nozzle memberis designed to have a small gap between the outer peripheral surfaceand an inner peripheral surface of the metal pipe material.

The clamp mechanismis a mechanism that is provided on an outer peripheral portion of the nozzle memberand that clamps the metal pipe material. The clamp mechanismseals the metal pipe materialby deforming the clamp mechanismitself in the radial direction. In the present embodiment, the clamp mechanismclamps the metal pipe materialby contracting in response to an external force applied from the outer peripheral side. The clamp mechanismis disposed at a position corresponding to the nozzle memberand the shaft portionof the nozzle base memberin the axial direction D. The clamp mechanismis a tubular body including a plurality of slitsA andB, and includes a colletthat is contractible and restorable in the radial direction. A detailed configuration of the colletwill be described below.

The hydraulic cylinderincludes a cylinder main bodyand a cylinder rod. The cylinder main bodyis disposed on the outer peripheral side with respect to the clamp mechanism. The cylinder main bodyis fixed to the extension portionof the nozzle base member. The cylinder rodis disposed between the clamp mechanismand the cylinder main bodyin the radial direction. In addition, a front region of the cylinder rodin the axial direction Dis disposed to be in contact with the clamp mechanismon the inner peripheral surface. The cylinder rodincludes a tapered surfaceon an inner peripheral surface on a front end side. The tapered surfaceis inclined toward the outer peripheral side from the front side to the rear side. In addition, a rear region of the cylinder rodin the axial direction Dis inserted into a guide groove portionof the extension portionof the nozzle base memberto be capable of reciprocating motion.

A hydraulic chamber(see) and a hydraulic chamber(see) are formed between the cylinder main bodyand the cylinder rod. The hydraulic chamberis disposed on the rear side with respect to the hydraulic chamber. A hydraulic oil OLis supplied to the hydraulic chamberfrom a hydraulic flow path Lof the cylinder main body. As a result, the cylinder rodmoves to the front side by a hydraulic pressure of the hydraulic oil OL. The hydraulic oil OL(see) is supplied to the hydraulic chamberfrom a hydraulic flow path Lof the cylinder main body. As a result, the cylinder rodmoves to the rear side by a hydraulic pressure of the hydraulic oil OL. A plurality of sealing members such as an O-ring are provided between the cylinder rodand the cylinder main body. In addition, the plurality of sealing members are provided between the cylinder rodand the guide groove portion.

The colletwill be described with reference to. As illustrated in, the colletincludes a tubular main body, a front end portionon the front side in the axial direction D, and a rear end portionon the rear side in the axial direction D. The plurality of slitsA andB extending in the axial direction Dare formed in the main body. The slitsA andB penetrate the main bodyin the radial direction, and extend over the entire main bodyin the axial direction D. The slitsA andB are alternately disposed in the circumferential direction. The slitA is formed in the main bodyand the rear end portionand is not formed in the front end portion. Therefore, at the position of the slitA, the colletis divided in the circumferential direction at the rear end portion, and is connected in the circumferential direction at the front end portion. The slitB is formed in the main bodyand the front end portionand is not formed in the rear end portion. Therefore, at the position of the slitB, the colletis divided in the circumferential direction at the front end portion, and is connected in the circumferential direction at the rear end portion.

As described above, the collethas a structure in which a plurality of tube walls are connected to each other in a strip shape in the circumferential direction. When the external force is applied to the colletfrom the outer peripheral side, the colletis deformed so that the gap between the slitsA andB is crushed. Therefore, the colletis deformed to contract in the radial direction as the circumferential length decreases. Meanwhile, when the external force is released, the respective slitsA andB return to an original gap size due to an elastic action of a spring. Therefore, the colletis automatically restored to an original shape.

The colletincludes a tapered structureprovided on the front side and a tapered structureprovided on the rear side. The tapered structureis provided on an outer peripheral surface side of the collet. The tapered structureis inclined to widen toward the outer peripheral side from the front end portionto the rear side. The tapered structureis inclined to widen toward the outer peripheral side from the rear end portionto the front side. As a result, the colletis deformed in the radial direction in response to the external force applied through the tapered structuresandas the cylinder rodmoves to the rear side in the axial direction D. The modification aspect will be described below. An outer peripheral surfaceof the colletbetween the tapered structuresandextends parallel to the axial direction D. The colletis a member made of metal. Heat-resistant spring steel is preferably used as the metal material. Therefore, when the clamp mechanismis made of metal, the clamp mechanismcan seal the metal pipe materialby the metal touch during the clamping.

The dispositions of the colletin the sealing mechanismwill be described with reference to. An inner peripheral surfaceof the colletis disposed to face the outer peripheral surfaceof the nozzle memberand an outer peripheral surfaceof the shaft portionof the nozzle base memberin the radial direction. The tapered structureon the front side is disposed to make surface contact with the tapered surfaceof the cylinder rod. The tapered structureon the rear side is disposed to make surface contact with the tapered surfaceformed on the nozzle base member. In addition, a restricting surfacethat restricts the movement of the colletis formed on an inner side of the tapered surfaceof the nozzle base member.

A clamping/sealing mode by the clamp mechanismusing the colletwill be described. A state illustrated inis a state before the clamping. In this state, the colletis in a non-contraction state. When the hydraulic oil OLis supplied to the hydraulic chamberfrom this state, the cylinder rodmoves to the rear side as illustrated in. The cylinder rodmoves the entire colletthat is in contact with the tapered structureto the rear side. The colletis guided by the tapered surfaceand moves rearward to the position of the restricting surfaceHere, the colletmoves to the rear side in a state of being in contact with the tapered surfaceat a location of the tapered structure.

Therefore, the colletreceives the external force that acts from the outer peripheral side toward the inner peripheral side via the tapered structure, from the tapered surfaceAs a result, the colletis deformed to contract toward the inner peripheral side as the slitsA andB are narrowed. In addition, the colletmoves to the rear side in a state of being in contact with the tapered surfaceat a location of the tapered structure. Therefore, the colletreceives the external force that acts from the outer peripheral side toward the inner peripheral side via the tapered structure, from the tapered surface. As a result, the colletis deformed to contract toward the inner peripheral side as the slitsA andB are narrowed.

In this way, the colletcontracts to the inner peripheral side, and thus the colletcan clamp the metal pipe materialbetween the colletand the nozzle member. In such a case, the gap between the slitsA andB of the colletis reduced. The metal pipe materialis deformed by the clamping, and the inner peripheral surface of the metal pipe materialand the outer peripheral surfaceof the nozzle membercome into close contact with each other, so that the metal pipe materialis in a sealed state so that a high-pressure airflow from the inside to the outside of the metal pipe materialis not leaked.

When the forming of the metal pipe materialis completed, as illustrated in, the hydraulic oil OLis supplied to the hydraulic chamberto move the cylinder rodto the front side. In such a case, the external force acting on the colletis released. The colletis restored and expanded in diameter by the spring action. In such a case, the entire colletmoves to an original position on the front side such that the colletis guided by the tapered structureas the colletis expanded in diameter.

The nozzle base membercan supply cooling air to the colletthrough a path formed by the flow path Lwith respect to the restricting surfaceor a path using the guide groove portion. In addition, the colletincludes the plurality of slitsA andB extending substantially over the entire axial direction D. Therefore, in a state in which a heat transfer area is widened by the plurality of slitsA andB, the cooling using the cooling air is performed.

Hereinafter, the operations and effects of the forming deviceaccording to the present embodiment will be described.

In the sealing mechanism, the nozzle memberis disposed in the inner portion of the metal pipe material, and the clamp mechanismis provided on the outer peripheral side of the nozzle member. Therefore, the fluid supplied from the nozzle memberinto the metal pipe materialis prevented from leaking to the outside of the metal pipe materialby the sealing of the clamp mechanism. Here, the clamp mechanismseals the metal pipe materialby deforming the clamp mechanismitself in the radial direction. Since the mechanism itself for clamping the metal pipe materialis deformed to perform the sealing, it is possible to select a material having higher heat resistance than a sealing member such as a resin-based O-ring, as a material of the clamp mechanism. As a result, it is possible to perform sealing in a state in which the influence of the high-temperature metal pipe materialis suppressed.

For example, in a case in which the metal pipe materialis heated only by the energization heating, the sealing using the O-ring in the related art can also be used because the temperature on the end portion side with respect to the electrode does not reach a high level, but, in the heating method in which the entire metal pipe materialincluding the end portion is heated to a high temperature by the furnace heating, it is difficult to use the O-ring. In contrast, in the present invention, even when the furnace heating is performed, it is possible to perform high-quality sealing.

The clamp mechanismmay clamp the metal pipe materialby contracting in response to the external force applied from the outer peripheral side. As a result, the clamp mechanism can be configured with a simple design.

The clamp mechanismmay seal the metal pipe materialby the metal touch during the clamping by forming the clamp mechanismwith metal. As a result, it is possible to perform sealing in a state in which the influence of the high-temperature metal pipe materialis suppressed.

The clamp mechanismmay be a tubular body including the plurality of slitsA andB, and include the colletthat is contractible and restorable in the radial direction. In this case, the clamping and the sealing can be performed with a simple structure.

The clamp mechanismmay include tapered structuresand, and may be deformed in the radial direction in response to the external force applied via the tapered structuresandas the clamp mechanismmoves in the axial direction D. In this case, the operation of the clamp mechanismthat moves in the axial direction Dcan be easily converted into the external force for deforming the clamp mechanismin the radial direction.

In addition, the forming deviceincludes the sealing mechanismthat performs the sealing against the leakage of the fluid from the metal pipe materialwhen the fluid is supplied by the fluid supply unitinto the metal pipe materialthat is heated by the heating unit (here, external heating furnace). Therefore, the fluid supplied from the fluid supply unitinto the metal pipe materialis prevented from leaking to the outside of the metal pipe materialby the sealing of the sealing mechanism. Here, the sealing mechanismperforms the sealing by contact between the metal pipe materialand the non-resin material, without applying the axial force to the metal pipe material. As a result, it is possible to select a non-resin material having higher heat resistance than a sealing member such as a resin-based O-ring, as a material of the sealing mechanism. As a result, it is possible to perform sealing in a state in which the influence of the high-temperature metal pipe materialis suppressed.

The nozzle memberof the fluid supply unitmay be disposed in the inner portion of the metal pipe material, and the colletof the sealing mechanismmay be disposed on the outer portion of the metal pipe material, and perform the sealing using the inner peripheral surfacethat is the sealing surface moved by the sealing mechanismin the radial direction toward the metal pipe materialwhen the fluid is supplied by the fluid supply unit. In this case, the sealing mechanismcan press the sealing surface against the metal pipe materialin the radial direction, and thus it is possible to more suppress the leakage of the fluid from the metal pipe material.

The forming devicemay further include the holding unitfor the sealing so that the metal pipe materialdoes not buckle when the fluid is supplied by the fluid supply unit. In a case in which the nozzle memberof the fluid supply unitis mounted in the metal pipe material, even when the pressing is performed with a certain pressing force, the holding unitcan prevent the metal pipe materialfrom shifting in the pressing direction of the nozzle memberof the fluid supply unit. Alternatively, the holding unitcan hold the metal pipe materialtransported from a transport device for the metal pipe material.

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

For example, the clamp mechanismmay clamp the metal pipe materialby expanding in response to the external force applied from the inner peripheral side. As a result, a compact configuration with a small diameter can be obtained.

In addition, the clamp mechanismis not limited to the mechanism including the collet, and can be changed as appropriate as long as the mechanism can perform the clamping and the sealing.

In addition, the structure of the sealing mechanismis not limited to the structures in, and various structures may be changed as appropriate.

In addition, in the above-described embodiment, the furnace heating is adopted as the method of heating the metal pipe material, but the energization heating using the electrode may be adopted.