Patent Description:
In the related art, there is known a forming system for forming a metal pipe from a cylindrical metal pipe material having a welded portion in which end portions of a plate material are welded to each other. As such a forming system, for example, PTL <NUM> discloses a forming system which includes a forming apparatus having a set of dies and a heating and expanding part which heats a metal pipe material disposed between the set of dies and supplies a gas into the metal pipe material to expand the metal pipe material.

In the forming system described above, when the metal pipe material expands, a plate thickness of the metal pipe material becomes thin according to a pipe expansion rate of the metal pipe material. Here, the smaller the deformation resistance of the metal pipe material, the larger the pipe expansion rate of the metal pipe material is, and thus the plate thickness becomes thinner.

Incidentally, there is a case where the metal pipe material is made into a pipe shape by rounding a metal plate material and welding a connection portion. In a case where a metal pipe material having such a welded portion is used, if the metal pipe material is heated, the deformation resistance of the welded portion tends to be reduced compared to the plate material portion. For this reason, in the forming system described above, if an attempt to heat the metal pipe material and supply a gas into the metal pipe material to expand it is made, the plate thickness of the welded portion of the metal pipe material heated to a high temperature becomes particularly thin locally, and thus there is a concern that the metal pipe material may be damaged starting from the welded portion.

Therefore, the present invention has an object to provide a forming system and a forming method, in which it is possible to suppress breakage of a metal pipe material starting from a welded portion at the time of forming of a metal pipe.

A solution to the aforementioned problem is provided by forming systems and forming methods as defined in the independent claims <NUM>, <NUM>, <NUM>, and <NUM>.

In the forming system and the forming method of claims <NUM> and <NUM>, when the heated metal pipe material expands, the welded portion of the metal pipe material comes into contact with the surface of the die prior to the portion which is located on the straight line connecting the longest position and the center of the metal pipe material. Here, if the heated metal pipe material expands and comes into contact with the surface of the die, the portion which is in contact with the die is cooled due to heat conduction, and thus the deformation resistance of the portion increases. Therefore, in the forming system and the forming method, at the time of the forming of the metal pipe, the welded portion comes into contact with the die at an early timing, and thus the deformation resistance of the welded portion increases at an early timing, and therefore, it is possible to suppress the plate thickness of the welded portion becoming particularly thin locally. Accordingly, it is possible to suppress the breakage of the metal pipe material starting from the welded portion at the time of the forming of the metal pipe.

In the forming system and the forming method of claims <NUM> and <NUM>, when the heated metal pipe material expands, the welded portion of the metal pipe material, which is located on the straight line connecting the shortest position and the center of the metal pipe material, first comes into contact with the surface of the die. Here, if the heated metal pipe material expands and comes into contact with the surface of the die, the portion which is in contact with the die is cooled due to heat conduction, and thus the deformation resistance of the portion increases. Therefore, in the forming system and the forming method, at the time of the forming of the metal pipe, the welded portion first comes into contact with the die, and thus the deformation resistance of the welded portion first increases, and therefore, it is possible to suppress the plate thickness of the welded portion becoming particularly thin locally. Accordingly, it is possible to particularly suppress the breakage of the metal pipe material starting from the welded portion at the time of the forming of the metal pipe.

In the forming system according to an aspect of the present invention, the supply device may include a rotating part capable of rotating the metal pipe material around a central axis, and a transport part capable of gripping the metal pipe material and capable of transporting the gripped metal pipe material to the forming apparatus, and the control unit may control an operation of the rotating part so as to adjust a direction in which the welded portion is located with respect to the center of the metal pipe material in a case of being viewed from the extension direction, by rotating the metal pipe material around the central axis by the rotating part, and control an operation of the transport part so as to grip and transport the metal pipe material to the forming apparatus by the transport part, when the metal pipe material is supplied to the forming apparatus by the supply device. In this case, it is possible to adjust the direction in which the welded portion is located with respect to the center of the metal pipe material by the rotating part, and to transport the metal pipe material to the forming apparatus by the transport part. Accordingly, the operation and effects described above can be suitably exhibited.

In the forming system according to an aspect of the present invention, the supply device may include a rotation and transport part composed of an articulated arm capable of gripping the metal pipe material and rotating the gripped metal pipe material around a central axis and capable of transporting the metal pipe material to the forming apparatus, and the control unit may control an operation of the rotation and transport part so as to adjust a direction in which the welded portion is located with respect to the center of the metal pipe material in a case of being viewed from the extension direction, by gripping the metal pipe material and rotating the metal pipe material around the central axis by the rotation and transport part, and to transport the metal pipe material to the forming apparatus, when the metal pipe material is supplied to the forming apparatus by the supply device. In this case, it is possible to transport the metal pipe material to the forming apparatus while adjusting the direction in which the welded portion is located with respect to the center of the metal pipe material by the rotation and transport part. Accordingly, it is possible to shorten the time required to supply the metal pipe material to the forming apparatus by the supply device.

According to the forming system and the forming method according to the present invention, it becomes possible to suppress the breakage of the metal pipe material starting from the welded portion at the time of the forming of the metal pipe.

Hereinafter, an embodiment of a forming apparatus according to the present invention will be described with reference to the drawings. In each drawing, identical or corresponding portions are denoted by the same reference numerals, and overlapping description will be omitted.

<FIG> is a schematic configuration diagram showing a forming system of a first embodiment, and <FIG> is a perspective view showing an example of a metal pipe material. A forming system <NUM> shown in <FIG> is for forming a metal pipe <NUM> (refer to <FIG>) by using a cylindrical metal pipe material <NUM> having a welded portion 14b in which end portions 14a and 14a of a plate member are welded to each other, as shown in <FIG>. More specifically, the metal pipe material <NUM> is formed by rounding a flat plate-like metal thin plate into a cylindrical shape and welding the facing end portions 14a and 14a in a state of being brought into contact with each other. The welded portion 14b where the metal pipe material <NUM> is welded in this manner extends along a central axis L of the metal pipe material <NUM>. The central axis L of the metal pipe material <NUM> is parallel to an extension direction D of the metal pipe material <NUM>. Then, as shown in <FIG>, the forming system <NUM> includes a forming apparatus <NUM>, a position detection unit <NUM>, a supply device <NUM>, an unloading device <NUM>, and a control device <NUM>.

First, the configuration of the forming apparatus <NUM> will be described. <FIG> is a schematic configuration diagram showing the forming apparatus in <FIG>, and <FIG> is a functional block diagram showing the forming system of <FIG>. As shown in <FIG> and <FIG>, the forming apparatus <NUM> includes a set of blow forming dies (dies) <NUM> composed of an upper die <NUM> and a lower die <NUM>, and a heating and expanding part <NUM> which heats the metal pipe material <NUM> disposed between the set of blow forming dies <NUM> and supplies a gas into the metal pipe material <NUM> to expand the metal pipe material <NUM>.

The heating and expanding part <NUM> shown in <FIG> is configured to include a drive mechanism <NUM> which moves at least one of the upper die <NUM> and the lower die <NUM>, a pipe holding mechanism <NUM> which holds the metal pipe material <NUM> between the upper die <NUM> and the lower die <NUM>, a heating mechanism <NUM> which energizes and heats the metal pipe material <NUM> held by the pipe holding mechanism <NUM>, a gas supply unit <NUM> for supplying a high-pressure gas (gas) into the metal pipe material <NUM> held and heated between the upper die <NUM> and the lower die <NUM>, a pair of gas supply mechanisms <NUM> and <NUM> for supplying the gas from the gas supply unit <NUM> into the metal pipe material <NUM> held by the pipe holding mechanism <NUM>, a water circulation mechanism <NUM> which forcibly water-cools the blow forming dies <NUM>, and a forming apparatus control unit <NUM> which controls the drive of the drive mechanism <NUM>, the drive of the pipe holding mechanism <NUM>, the drive of the heating mechanism <NUM>, and the gas supply of the gas supply unit <NUM>, as shown in <FIG>.

The lower die <NUM> which is one of the blow forming dies <NUM> is fixed to a base <NUM>. The lower die <NUM> is formed of a large steel block and has a cavity (recessed portion) <NUM> having a desired shape on the upper surface thereof. A cooling water passage <NUM> is formed in the lower die <NUM>, and the lower die <NUM> is provided with a thermocouple <NUM> inserted from below at substantially the center. The thermocouple <NUM> is supported by a spring <NUM> so as to be movable up and down. The cavity <NUM> is formed in a shape according to the shape (outer shape) of the metal pipe <NUM> to be formed (refer to <FIG>).

Further, a space 11a is provided in the vicinity of each of the right and left ends (right and left ends in <FIG>) of the lower die <NUM>, and electrodes <NUM> and <NUM> (lower electrodes) (described later), which are movable parts of the pipe holding mechanism <NUM>, and the like are disposed in the spaces 11a so as to be able to move up and down. Then, the metal pipe material <NUM> is placed on the lower electrodes <NUM> and <NUM>, whereby the lower electrodes <NUM> and <NUM> come into contact with the metal pipe material <NUM> which is disposed between the upper die <NUM> and the lower die <NUM>. In this way, the lower electrodes <NUM> and <NUM> are electrically connected to the metal pipe material <NUM>.

Insulating materials <NUM> for preventing electric conduction are provided between the lower die <NUM> and the lower electrode <NUM>, below the lower electrode <NUM>, between the lower die <NUM> and the lower electrode <NUM>, and below the lower electrode <NUM>. Each of the insulating materials <NUM> is fixed to an advancing and retracting rod <NUM> which is a movable portion of an actuator (not shown) configuring the pipe holding mechanism <NUM>. The actuator is for moving the lower electrodes <NUM> and <NUM> and the like up and down, and a fixed portion of the actuator is held on the base <NUM> side together with the lower die <NUM>.

The upper die <NUM> which is the other die of the blow forming dies <NUM> is fixed to a slide <NUM> (described later) configuring the drive mechanism <NUM>. The upper die <NUM> is formed of a large steel block and has a cooling water passage <NUM> formed in the interior thereof, and a cavity (recessed portion) <NUM> having a desired shape is provided on the lower surface of the upper die <NUM>. The cavity <NUM> is provided at a position facing the cavity <NUM> of the lower die <NUM>. The cavity <NUM> is formed in a shape according to the shape (outer shape) of the metal pipe <NUM> to be formed (refer to <FIG>).

Similar to the lower die <NUM>, a space 12a is provided in the vicinity of each of the right and left ends (right and left ends in <FIG>) of the upper die <NUM>, and electrodes <NUM> and <NUM> (upper electrodes) (described later), which are movable parts of the pipe holding mechanism <NUM>, and the like are disposed in the spaces 12a so as to be movable up and down. Then, the upper electrodes <NUM> and <NUM> move downward in a state where the metal pipe material <NUM> is placed on the lower electrodes <NUM> and <NUM>, whereby the upper electrodes <NUM> and <NUM> come into contact with the metal pipe material <NUM> disposed between the upper die <NUM> and the lower die <NUM>. In this way, the upper electrodes <NUM>, <NUM> are electrically connected to the metal pipe material <NUM>.

Insulating materials <NUM> for preventing electric conduction are provided between the upper die <NUM> and the upper electrode <NUM>, above the upper electrode <NUM>, between the upper die <NUM> and the upper electrode <NUM>, and above the upper electrode <NUM>. Each of the insulating materials <NUM> is fixed to an advancing and retracting rod <NUM> which is a movable portion of the actuator configuring the pipe holding mechanism <NUM>. The actuator is for moving the upper electrodes <NUM> and <NUM> and the like up and down, and a fixed portion of the actuator is held on the slide <NUM> side of the drive mechanism <NUM> together with the upper die <NUM>.

A semicircular arc-shaped concave groove 18a corresponding to the outer peripheral surface of the metal pipe material <NUM> is formed in each of the surfaces of the electrodes <NUM> and <NUM>, which face each other, in the right side portion of the pipe holding mechanism <NUM> (refer to <FIG>), and the metal pipe material <NUM> can be placed so as to exactly fit to the portion of the concave groove 18a. Similar to the concave groove 18a, a semicircular arc-shaped concave groove corresponding to the outer peripheral surface of the metal pipe material <NUM> is formed in each of exposed surfaces of the insulating materials <NUM> and <NUM>, which face each other, in the right side portion of the pipe holding mechanism <NUM>. Further, a tapered concave surface 18b in which the periphery is recessed to be inclined in a tapered shape toward the concave groove 18a is formed on the front surface of the electrode <NUM> (the surface in an outer direction of the die). Accordingly, a configuration is made such that, if the metal pipe material <NUM> is clamped from an up-down direction at the right side portion of the pipe holding mechanism <NUM>, the outer periphery of the right end portion of the metal pipe material <NUM> can be exactly surrounded so as to be in close contact over the entire circumference.

A semicircular arc-shaped concave groove 17a corresponding to the outer peripheral surface of the metal pipe material <NUM> is formed in each of the surfaces of the electrodes <NUM> and <NUM>, which face each other, in the left side portion of the pipe holding mechanism <NUM> (refer to <FIG>), and the metal pipe material <NUM> can be placed so as to exactly fit to the portion of the concave groove 17a. Similar to the concave groove 18a, a semicircular arc-shaped concave groove corresponding to the outer peripheral surface of the metal pipe material <NUM> is formed in each of exposed surfaces of the insulating materials <NUM> and <NUM>, which face each other, in the left side portion of the pipe holding mechanism <NUM>. Further, a tapered concave surface 17b in which the periphery is recessed to be inclined in a tapered shape toward the concave groove 17a is formed on the front surface of the electrode <NUM> (the surface in the outer direction of the die). Accordingly, a configuration is made such that, if the metal pipe material <NUM> is clamped from the up-down direction at the left side portion of the pipe holding mechanism <NUM>, the outer periphery of the left end portion of the metal pipe material <NUM> can be exactly surrounded so as to be in close contact over the entire circumference.

As shown in <FIG>, the drive mechanism <NUM> includes the slide <NUM> for moving the upper die <NUM> such that the upper die <NUM> and the lower die <NUM> are combined with each other, a shaft <NUM> for generating a driving force for moving the slide <NUM>, and a connecting rod <NUM> for transmitting the driving force generated by the shaft <NUM> to the slide <NUM>. The shaft <NUM> extends in a right-left direction above the slide <NUM>, is rotatably supported, and has an eccentric crank 82a which protrudes and extends from the right and left ends at a position separated from the center thereof. The eccentric crank 82a and a rotary shaft 81a provided above the slide <NUM> and extending in the right-left direction are connected to each other by the connecting rod <NUM>. In the drive mechanism <NUM>, the height in the up-down direction of the eccentric crank 82a is changed by controlling the rotation of the shaft <NUM> by the forming apparatus control unit <NUM>, and the up-and-down movement of the slide <NUM> can be controlled by transmitting the positional change of the eccentric crank 82a to the slide <NUM> through the connecting rod <NUM>. Here, the oscillation (rotational movement) of the connecting rod <NUM>, which occurs when the positional change of the eccentric crank 82a is transmitted to the slide <NUM>, is absorbed by the rotary shaft 81a. The shaft <NUM> rotates or stops in response to the drive of a motor or the like, which is controlled by the forming apparatus control unit <NUM>, for example.

The heating mechanism <NUM> includes a power source <NUM>, a bus bar <NUM> extending from the power source <NUM>, and a switch <NUM> provided in the bus bar <NUM>. The bus bar <NUM> is connected to only the lower electrodes <NUM> and <NUM> and is a conductor for supplying the electric power from the power source <NUM> to the electrodes <NUM> and <NUM> connected thereto. The forming apparatus control unit <NUM> controls the heating mechanism <NUM> to heat the metal pipe material <NUM> to a quenching temperature (a temperature equal to or higher than an AC3 transformation temperature).

Each of the pair of gas supply mechanisms <NUM> includes a cylinder unit <NUM>, a cylinder rod <NUM> which advances and retreats in accordance with the operation of the cylinder unit <NUM>, and a seal member <NUM> connected to the tip of the cylinder rod <NUM> on the pipe holding mechanism <NUM> side. The cylinder unit <NUM> is placed on and fixed to a block <NUM>. A tapered surface <NUM> which is tapered is formed on the tip of the seal member <NUM>, and is configured in a shape which is fitted to the tapered concave surfaces 17b and 18b of the electrodes <NUM> and <NUM> (refer to <FIG>). A gas passage <NUM> which extends from the cylinder unit <NUM> side toward the tip and through which the high-pressure gas supplied from the gas supply unit <NUM> flows, as shown in detail in <FIG>, is provided in the seal member <NUM>.

The gas supply unit <NUM> includes a gas source <NUM>, an accumulator <NUM> for storing the gas supplied by the gas source <NUM>, a first tube <NUM> extending from the accumulator <NUM> to the cylinder unit <NUM> of the gas supply mechanism <NUM>, a pressure control valve <NUM> and a switching valve <NUM> provided in the first tube <NUM>, a second tube <NUM> extending from the accumulator <NUM> to the gas passage <NUM> formed in the seal member <NUM>, and a pressure control valve <NUM> and a check valve <NUM> provided in the second tube <NUM>. The pressure control valve <NUM> plays a role of supplying a gas having an operating pressure adapted to a pressing force of the seal member <NUM> against the metal pipe material <NUM> to the cylinder unit <NUM>. The check valve <NUM> plays a role of preventing the high-pressure gas from flowing backward in the second tube <NUM>. The pressure control valve <NUM> provided in the second tube <NUM> plays a role of supplying a gas having an operating pressure for expanding the metal pipe material <NUM> to the gas passage <NUM> of the seal member <NUM> by the control of the forming apparatus control unit <NUM>.

The forming apparatus control unit <NUM> can supply a gas having a desired operating pressure into the metal pipe material <NUM> by controlling the pressure control valve <NUM> of the gas supply unit <NUM>. The forming apparatus control unit <NUM> may control the pressure control valve <NUM> of the gas supply unit <NUM> so as to be able to perform the supply (primary blow) of a high-pressure gas having a relatively low pressure and the supply (secondary blow) of a high-pressure gas having a relatively high pressure into the metal pipe material <NUM>. Further, the forming apparatus control unit <NUM> acquires temperature information from the thermocouple <NUM> from information which is transmitted from (A) shown in <FIG>, and controls the drive mechanism <NUM>, the switch <NUM>, and the like.

The water circulation mechanism <NUM> includes a water tank <NUM> for storing water, a water pump <NUM> for pumping up the water stored in the water tank <NUM>, pressurizing it, and sending it to the cooling water passage <NUM> of the lower die <NUM> and the cooling water passage <NUM> of the upper die <NUM>, and a pipe <NUM>. Although omitted, a cooling tower for lowering a water temperature or a filter for purifying water may be provided in the pipe <NUM>.

Next, the configuration of the position detection unit <NUM> shown in <FIG> and <FIG> will be described. The position detection unit <NUM> detects the direction in which the welded portion 14b is located with respect to a center C of the metal pipe material <NUM> in a case of being viewed from the extension direction D of the metal pipe material <NUM>, before the metal pipe material <NUM> is supplied to the forming apparatus <NUM> by the supply device <NUM> (described later). As shown in <FIG> and <FIG>, the position detection unit <NUM> includes optical means <NUM> and a welding position determination unit <NUM>.

The optical means <NUM> is, for example, an optical camera, and photographs the outer peripheral surface of the metal pipe material <NUM> to acquire imaging data. The metal pipe material <NUM> is rotated around the central axis L by a rotating part <NUM> of the supply device <NUM> (described later) while the metal pipe material <NUM> is being photographed by the optical means <NUM>. In this way, the optical means <NUM> can perform photographing over the entire circumference of the outer peripheral surface of the metal pipe material <NUM>. The optical means <NUM> outputs the acquired imaging data to the welding position determination unit <NUM>. The welding position determination unit <NUM> performs image processing on the imaging data input from the optical means <NUM>, thereby detecting the position of the welded portion 14b on the outer peripheral surface of the metal pipe material <NUM>. By the above, the welding position determination unit <NUM> detects the direction in which the welded portion 14b is located with respect to the center C of the metal pipe material <NUM>.

The position detection unit <NUM> is not limited to such a configuration, and a known configuration can be applied thereto. For example, the optical means <NUM> may be configured to acquire imaging data by photographing the outer peripheral surface of the metal pipe material <NUM> by using a laser, instead of the optical camera. Further, the position detection unit <NUM> may have a configuration for rotating the metal pipe material <NUM> around the central axis L, and in that case, the rotating part <NUM> of the supply device <NUM> may not be used in order to rotate the metal pipe material <NUM> around the central axis L.

Next, the configuration of the supply device <NUM> will be described. The supply device <NUM> is for supplying the metal pipe material <NUM> to the forming apparatus <NUM>. The supply device <NUM> includes the rotating part <NUM> and a transport part <NUM>. The rotating part <NUM> includes, for example, two rollers disposed parallel to each other at the same height and at an interval smaller than the diameter of the metal pipe material <NUM>. At least one of the two rollers configuring the rotating part <NUM> is rotationally driven by a motor. In this way, the rollers are rotationally driven in a state where the metal pipe material <NUM> is placed on the two rollers configuring the rotating part <NUM>, and thus the metal pipe material <NUM> is rotated around the central axis L.

The transport part <NUM> is capable of gripping the metal pipe material <NUM> and capable of transporting the gripped metal pipe material <NUM> to the forming apparatus <NUM>. The transport part <NUM> is, for example, a robot arm in which a gripping part for gripping the metal pipe material <NUM> is provided at a tip portion of the arm (refer to <FIG>). The transport part <NUM> can move the gripping part up and down, horizontally, and the like in a state where the metal pipe material <NUM> is gripped by the gripping part.

Next, the configuration of the unloading device <NUM> will be described. The unloading device <NUM> unloads the metal pipe <NUM> (refer to <FIG>) formed from the metal pipe material <NUM> by the forming apparatus <NUM>, from the forming apparatus <NUM>. The unloading device <NUM> has the same configuration as the transport part <NUM> of the supply device <NUM>. The unloading device <NUM> is capable of gripping the metal pipe <NUM> and capable of unloading the gripped metal pipe <NUM> from the forming apparatus <NUM>. The unloading device <NUM> is, for example, a robot arm in which a gripping part for gripping the metal pipe <NUM> is provided at a tip portion of the arm. The unloading device <NUM> can move the gripping part up and down, horizontally, and the like in a state where the metal pipe <NUM> is gripped by the gripping part.

Next, the configuration of the control device <NUM> will be described. The control device <NUM> controls the operations of the position detection unit <NUM>, the supply device <NUM>, and the unloading device <NUM>, as shown in <FIG> and <FIG>. The control device <NUM> includes a storage unit <NUM> and a supply device control unit <NUM>.

The storage unit <NUM> stores information on a longest position R1 that is a position at which the distance from the center C of the metal pipe material <NUM> is the longest, on the surface of the blow forming die <NUM>, in a case of being viewed from the extension direction D of the metal pipe material <NUM> in a state where the metal pipe material <NUM> is disposed between the set of blow forming dies <NUM> (refer to <FIG>). The longest position R1 is a position at which the distance from the center C of the metal pipe material <NUM> is the longest, on the surface of the blow forming die <NUM>, in a space which is formed by the cavity <NUM> of the lower die <NUM> and the cavity <NUM> of the upper die <NUM> of the blow forming dies <NUM> in a state where the metal pipe material <NUM> is disposed between the set of blow forming dies <NUM> when supplying the high-pressure gas into the metal pipe material <NUM>. Further, the information on the longest position R1 may be, for example, the position coordinates of the longest position R1, or may be an angle at which the longest position R1 is located with respect to a straight line (for example, a straight line extending in the horizontal direction) passing through the center C of the metal pipe material <NUM>, in a case of being viewed from the extension direction D of the metal pipe material <NUM> in a state where the metal pipe material <NUM> is disposed between the set of blow forming dies <NUM>.

The supply device control unit (control unit) <NUM> controls, based on the information on the longest position R1 stored in the storage unit <NUM>, the supply of the metal pipe material <NUM> to the forming apparatus <NUM> by the supply device <NUM> such that the welded portion 14b is not located on a straight line P1 connecting the longest position R1 and the center C of the metal pipe material <NUM> in a case of being viewed from the extension direction D of the metal pipe material <NUM> in a state where the metal pipe material <NUM> is disposed between the set of blow forming dies <NUM>.

More specifically, the supply device control unit <NUM> controls the operation of the rotating part <NUM> so as to adjust the direction in which the welded portion 14b is located with respect to the center C of the metal pipe material <NUM> in a case of being viewed from the extension direction D of the metal pipe material <NUM>, by rotating the metal pipe material <NUM> around the central axis C by the rotating part <NUM>, when the metal pipe material <NUM> is supplied to the forming apparatus <NUM> by the supply device <NUM>. Further, the supply device control unit <NUM> controls the operation of the transport part <NUM> so as to grip and transport the metal pipe material <NUM> to the forming apparatus <NUM> by the transport part <NUM>.

Next, a method of forming the metal pipe <NUM> by using the forming system <NUM> of this embodiment will be described. <FIG> is a flowchart showing the forming method.

As shown in <FIG>, first, in Step S10, the metal pipe material <NUM> is placed on a placing part. In this embodiment, the rotating part <NUM> of the supply device <NUM> is also used as the pacing part. A configuration (for example, a shelf, a pallet, or the like disposed at a predetermined position) separate from the rotating part <NUM> of the supply device <NUM> may be used as the placing part. Thereafter, the routine proceeds to Step S12.

In Step S12, the control device <NUM> controls the operations of the rotating part <NUM> of the supply device <NUM> and the position detection unit <NUM> to detect the direction in which the welded portion 14b of the metal pipe material <NUM> placed on the placing part is located. More specifically, the control device <NUM> acquires imaging data of the outer peripheral surface of the metal pipe material <NUM> photographed by the optical means <NUM> while the metal pipe material <NUM> is rotated around the central axis L by the rotating part <NUM> of the supply device <NUM>. The imaging data acquired by the optical means <NUM> is output to the welding position determination unit <NUM>. The welding position determination unit <NUM> performs image processing on the input imaging data to detect the position of the welded portion 14b on the outer peripheral surface of the metal pipe material <NUM>, and outputs the detected position to the control device <NUM>. Thereafter, the control device <NUM> proceeds to Step S14.

In Step S14, the control device <NUM> determines whether or not the adjustment of the direction in which the welded portion 14b is located with respect to the center C of the metal pipe material <NUM> is unnecessary. More specifically, the storage unit <NUM> of the control device <NUM> stores the information on the longest position R1 that is a position at which the distance from the center C of the metal pipe material <NUM> is the longest, on the surface of the blow forming die <NUM>, in a case of being viewed from the extension direction D of the metal pipe material <NUM> in a state where the metal pipe material <NUM> is disposed between the set of blow forming dies <NUM>. Then, when the welded portion 14b of the metal pipe material <NUM> is not located on the straight line P1 connecting the longest position R1 and the center C of the metal pipe material <NUM> in a case of being viewed from the extension direction D of the metal pipe material <NUM> in a state where the metal pipe material <NUM> is disposed between the set of blow forming dies <NUM>, the control device <NUM> determines that the adjustment of the direction in which the welded portion 14b is located with respect to the center C of the metal pipe material <NUM> is unnecessary. In a case where the control device <NUM> determines that the adjustment is unnecessary (Step S14: YES), the routine proceeds to Step S18. On the other hand, in a case where the control device <NUM> does not determine that the adjustment is unnecessary (Step S14: NO), the routine proceeds to Step S16.

In Step S16, the control device <NUM> controls the operation of the rotating part <NUM> of the supply device <NUM> to rotate the metal pipe material <NUM> around the central axis L. More specifically, the supply device control unit <NUM> of the control device <NUM> controls the operation of the rotating part <NUM> of the supply device <NUM>, based on the information on the longest position R1 stored in the storage unit <NUM>, thereby rotating the metal pipe material <NUM> around the central axis L such that the welded portion 14b of the metal pipe material <NUM> is not located on the straight line P1 connecting the longest position R1 and the center C of the metal pipe material <NUM> in a case of being viewed from the extension direction D of the metal pipe material <NUM> in a state where the metal pipe material <NUM> is disposed between the set of blow forming dies <NUM>. Then, the control device <NUM> stops the rotation of the metal pipe material <NUM> in a state where the adjustment of the direction in which the welded portion 14b is located with respect to the center C of the metal pipe material <NUM> becomes unnecessary. Thereafter, the routine proceeds to Step S18.

In Step S18, the control device <NUM> controls the operation of the transport part <NUM> of the supply device <NUM> to cause the transport part <NUM> to grip the metal pipe material <NUM> and transport the griped metal pipe material <NUM> to the forming apparatus <NUM>. The metal pipe material <NUM> is transported to the forming apparatus <NUM> and enters a state where it is placed between the set of blow forming dies <NUM>. Thereafter, the routine proceeds to Step S20.

In Step S20, the metal pipe material <NUM> is heated by the heating and expanding part <NUM> of the forming apparatus <NUM>, and a gas is supplied into the metal pipe material <NUM> to expand the metal pipe material <NUM>. In this way, the metal pipe <NUM> is formed from the metal pipe material <NUM> in the blow forming dies <NUM>. At this time, when the heated metal pipe material <NUM> expands, the welded portion 14b of the metal pipe material <NUM> comes into contact with the surface of the blow forming die <NUM> prior to a portion Q1 (refer to <FIG>) which is located on the straight line P1 connecting the longest position R1 and the center C of the metal pipe material <NUM>, and is cooled due to heat conduction. Thereafter, the routine proceeds to Step S22.

In Step S22, the control device <NUM> controls the operation of the unloading device <NUM> to grip the metal pipe <NUM> in the forming apparatus <NUM> and unload the gripped metal pipe <NUM> from the forming apparatus <NUM>. By the above, the forming of the metal pipe <NUM> by the forming system <NUM> of this embodiment is ended.

As described above, in the forming system <NUM> and the method of forming the metal pipe <NUM> by the forming system <NUM>, when the heated metal pipe material <NUM> expands, the welded portion 14b of the metal pipe material <NUM> comes into contact with the surface of the blow forming die <NUM> prior to the portion Q1 which is located on the straight line P1 connecting the longest position R1 and the center C of the metal pipe material <NUM>. Here, if the heated metal pipe material <NUM> expands and comes into contact with the surface of the blow forming die <NUM>, the portion which is in contact with the blow forming die <NUM> is cooled due to heat conduction, and thus the deformation resistance of the portion increases. Therefore, in the forming system <NUM> and the method of forming the metal pipe <NUM> by the forming system <NUM>, at the time of the forming of the metal pipe <NUM>, the welded portion 14b comes into contact with the blow forming die <NUM> at an earlier timing than the portion Q1 on the straight line P1, and thus the deformation resistance of the welded portion 14b increases at an early timing, and therefore, it is possible to suppress the plate thickness of the welded portion 14b becoming particularly thin locally. Accordingly, it is possible to suppress the breakage of the metal pipe material <NUM> starting from the welded portion 14b at the time of the forming of the metal pipe <NUM>.

Further, in the forming system <NUM>, the supply device <NUM> includes the rotating part <NUM> capable of rotating the metal pipe material <NUM> around the central axis C, and the transport part <NUM> capable of gripping the metal pipe material <NUM> and capable of transporting the gripped metal pipe material <NUM> to the forming apparatus <NUM>, and the supply device control unit <NUM> controls the operation of the rotating part <NUM> so as to adjust the direction in which the welded portion 14b is located with respect to the center C of the metal pipe material <NUM> in a case of being viewed from the extension direction D of the metal pipe material <NUM>, by rotating the metal pipe material <NUM> around the central axis C by the rotating part <NUM>, when supplying the metal pipe material <NUM> to the forming apparatus <NUM> by the supply device <NUM>, and controls the operation of the transport part <NUM> so as to grip and transport the metal pipe material <NUM> to the forming apparatus <NUM> by the transport part <NUM>. For this reason, the direction in which the welded portion 14b is located with respect to the center C of the metal pipe material <NUM> can be adjusted by the rotating part <NUM>, and the metal pipe material <NUM> can be transported to the forming apparatus <NUM> by the transport part <NUM>. Accordingly, the operation and effects of this embodiment can be suitably exhibited.

Further, in the forming system <NUM>, the position detection unit <NUM> is provided which detects the direction in which the welded portion 14b is located with respect to the center C of the metal pipe material <NUM> in a case of being viewed from the extension direction D of the metal pipe material <NUM>, before the metal pipe material <NUM> is supplied to the forming apparatus <NUM> by the supply device <NUM>. For this reason, the operation and effects of this embodiment can be suitably exhibited.

As shown in <FIG>, a forming system 1A of a second embodiment is mainly different from the forming system 1A of the first embodiment described above and the forming method of the metal pipe <NUM> by the forming system 1A in terms of the configuration of a supply device 120A. That is, the supply device 120A has a rotation and transport part <NUM> composed of an articulated arm capable of gripping the metal pipe material <NUM> and rotating the gripped metal pipe material <NUM> around the central axis L and capable of transporting the metal pipe material <NUM> to the forming apparatus <NUM>.

In the forming system 1A of the second embodiment having such a configuration, a supply device control unit 142A controls the operation of the rotation and transport part <NUM> so as to adjust the direction in which the welded portion 14b is located with respect to the center C of the metal pipe material <NUM> in a case of being viewed from the extension direction D of the metal pipe material <NUM>, by gripping the metal pipe material <NUM> and rotating the metal pipe material <NUM> around the central axis L by the rotation and transport part <NUM>, and to transport the metal pipe material <NUM> to the forming apparatus <NUM>, when the metal pipe material <NUM> is supplied to the forming apparatus <NUM> by the supply device 120A.

It goes without saying that also in the forming system 1A and the forming method of the second embodiment, the same operation and effects as those in the forming system <NUM> and the forming method of the first embodiment can be exhibited.

In addition, in the forming system 1A, the supply device 120A has the rotation and transport part <NUM> composed of an articulated arm capable of gripping the metal pipe material <NUM> and rotating the gripped metal pipe material <NUM> around the central axis C and capable of transporting the metal pipe material <NUM> to the forming apparatus <NUM>, and the supply device control unit 142A controls the operation of the rotation and transport part <NUM> so as to adjust the direction in which the welded portion 14b is located with respect to the center C of the metal pipe material <NUM> in a case of being viewed from the extension direction D of the metal pipe material <NUM>, by gripping the metal pipe material <NUM> and rotating the metal pipe material <NUM> around the central axis C by the rotation and transport part <NUM>, and to transport the metal pipe material <NUM> to the forming apparatus <NUM>, when the metal pipe material <NUM> is supplied to the forming apparatus <NUM> by the supply device 120A. For this reason, it is possible to transport the metal pipe material <NUM> to the forming apparatus <NUM> while adjusting the direction in which the welded portion 14b is located with respect to the center of the metal pipe material <NUM>, by the rotation and transport part <NUM>. Accordingly, it is possible to shorten the time required to supply the metal pipe material <NUM> to the forming apparatus <NUM> by the supply device 120A.

According to the invention,in the forming systems <NUM> and 1A, the control devices <NUM> and 140A include the storage units <NUM> and 141A which store information on a shortest position R2 (refer to <FIG>) that is a position at which the distance from the center C of the metal pipe material <NUM> is the shortest, on the surface of the blow forming die <NUM>, in a case of being viewed from the extension direction D of the metal pipe material <NUM> in a state where the metal pipe material <NUM> is disposed between the set of blow forming dies <NUM>, and the control devices <NUM> and 140A may include the supply device control units <NUM> and 142A which control, based on the information on the shortest position R2 stored in the storage units <NUM> and 141A, the supply of the metal pipe material <NUM> to the forming apparatus <NUM> by the supply devices <NUM> and 120A such that the welded portion 14b is located on a straight line P2 connecting the shortest position R2 and the center C of the metal pipe material <NUM> in a case of being viewed from the extension direction D of the metal pipe material <NUM> in a state where the metal pipe material <NUM> is disposed between the set of blow forming dies <NUM>. The shortest position R2 is a position at which the distance from the center C of the metal pipe material <NUM> is the shortest, on the surface of the blow forming die <NUM>, in the space which is formed by the cavity <NUM> of the lower die <NUM> and the cavity <NUM> of the upper die <NUM> of the blow forming dies <NUM>, in a state where the metal pipe material <NUM> is disposed between the set of blow forming dies <NUM> when supplying the high-pressure gas into the metal pipe material <NUM>. Further, the information on the shortest position R2 may be, for example, the position coordinates of the shortest position R2, or may be an angle at which the shortest position R2 is located with respect to a straight line (for example, a straight line extending in the horizontal direction) passing through the center C of the metal pipe material <NUM>, in a case of being viewed from the extension direction D of the metal pipe material <NUM> in a state where the metal pipe material <NUM> is disposed between the set of blow forming dies <NUM>.

Similarly, as the method of forming the metal pipe <NUM> by the forming system <NUM> or 1A, the metal pipe material <NUM> may be disposed between the set of blow forming dies <NUM> such that the welded portion 14b is located on the straight line P2 connecting the shortest position R2 which is a position at which the distance from the center C of the metal pipe material <NUM> is the shortest, on the surface of the blow forming die <NUM>, and the center C of the metal pipe material <NUM>, in a case of being viewed from the extension direction D of the metal pipe material <NUM> in a state where the metal pipe material <NUM> is disposed between the set of blow forming dies <NUM>.

In the forming system 1A and the method of forming the metal pipe <NUM> by the forming system 1A, when the heated metal pipe material <NUM> expands, the welded portion 14b of the metal pipe material <NUM>, which is located on the straight line P2 connecting the shortest position R2 and the center C of the metal pipe material <NUM>, first comes into contact with the surface of the blow forming die <NUM>. Here, if the heated metal pipe material <NUM> expands and comes into contact with the surface of the blow forming die <NUM>, the portion which is in contact with the blow forming die <NUM> is cooled due to heat conduction, and thus the deformation resistance of the portion increases. Therefore, in the forming systems <NUM> and 1A and the methods of forming the metal pipe <NUM> by the forming systems <NUM> and 1A, at the time of the forming of the metal pipe <NUM>, the welded portion 14b first comes into contact with the blow forming die <NUM>, and thus the deformation resistance of the welded portion 14b first increases, and therefore, it is possible to suppress the plate thickness of the welded portion 14b becoming particularly thin locally. Accordingly, it is possible to particularly suppress the breakage of the metal pipe material <NUM> starting from the welded portion 14b at the time of the forming of the metal pipe <NUM>.

Further, in the respective embodiments, the forming systems <NUM> and 1A may not be provided with the unloading device <NUM>. In this case, the formed metal pipe <NUM> may be unloaded from the forming apparatus <NUM> by, for example, the supply device <NUM> or 120A. According to this, the system configuration can be simplified, and a space adjacent to the forming apparatus <NUM> can be widely secured, so that a die replacement carriage or the like can be easily disposed in the space.

Subsequently, an example of the forming system and the forming method will be described with reference to <FIG>, <FIG>, and <FIG>.

<FIG> is a diagram showing the metal pipe material and measurement positions of the plate thickness and the temperature of the metal pipe in the example, and <FIG> and <FIG> are graphs showing simulation results of the plate thickness and the temperatures of the metal pipe material <NUM> at measurement positions <NUM> to <NUM> of <FIG> when forming the metal pipe <NUM> having the shape as shown in <FIG>. As shown in <FIG>, among the measurement positions <NUM> to <NUM>, the measurement position <NUM> is the longest position R1, and the measurement position <NUM> is the shortest position R2. Further, in this example, the supply of the high-pressure gas having a relatively low pressure (primary blow) and the supply of the high-pressure gas having a relatively high pressure (secondary blow) into the metal pipe material <NUM> were assumed to be performed in this order. In <FIG> and <FIG>, the plate thickness or the temperature is shown to be divided into measurement timings before the primary blow, after the primary blow, before the secondary blow, and after the secondary blow. Here, before the primary blow refers to before the blow forming work on the metal pipe material <NUM> is started, and after the secondary blow refers to after the blow forming work on the metal pipe material <NUM> is completed and the metal pipe <NUM> is formed.

When forming the metal pipe <NUM>, the set of blow forming dies <NUM> are closed to a halfway position in a state where the metal pipe material <NUM> is disposed between the set of blow forming dies <NUM>. In this state, the primary blow is performed, and thus the metal pipe material <NUM> is brought into contact with the blow forming die <NUM> on the straight line P2 connecting the measurement position <NUM> which is the shortest position R2 and the center of the metal pipe material <NUM>. Thereafter, the set of blow forming dies <NUM> is completely closed and the secondary blow is performed to complete the forming of the metal pipe <NUM>.

At the measurement position <NUM> which is the longest position R1, the heated metal pipe material <NUM> comes into contact with the blow forming die <NUM> at a late timing, thereby being cooled, and thus the deformation resistance increases at the late timing. As a result, as shown in <FIG>, the temperature of the metal pipe material <NUM> becomes excessively high at the measurement position <NUM>, and as shown in <FIG>, the plate thickness of the metal pipe material <NUM> becomes excessively thin at the measurement position <NUM>.

Claim 1:
A forming system (<NUM>) that forms a metal pipe (<NUM>) from a cylindrical metal pipe material (<NUM>) having a welded portion (14b) in which end portions (14a) of a plate material are welded to each other, the forming system (<NUM>) comprising:
a forming apparatus (<NUM>) which includes a set of dies (<NUM>), and a heating and expanding part (<NUM>) which heats the metal pipe material (<NUM>) disposed between the set of dies (<NUM>) and supplies a gas into the metal pipe material (<NUM>) to expand the metal pipe material (<NUM>); characterized in that the forming system further comprises:
a supply device (<NUM>) which rotates the metal pipe material (<NUM>) around a central axis of the metal pipe material (<NUM>) and supplies the metal pipe material (<NUM>) to the forming apparatus (<NUM>) ;
a position detection unit (<NUM>) which detects a direction in which the welded portion (14b) is located with respect to a center of the metal pipe material (<NUM>) in a case of being viewed from an extension direction, before the metal pipe material (<NUM>) is supplied to the forming apparatus (<NUM>) by the supply device (<NUM>); and
a control device (<NUM>) which includes a storage unit (<NUM>) and a control unit (<NUM>) and controls an operation of the supply device (<NUM>),
wherein
in a case where a position at which a distance from the center of the metal pipe material (<NUM>) is the longest, on a surface of any one of the dies of the set of dies (<NUM>), in a space which is formed by the cavity of the set of dies (<NUM>), in a case of being viewed from the extension direction of the metal pipe material (<NUM>) in a state where the metal pipe material (<NUM>) is disposed between the set of dies (<NUM>), is set to be a longest position (R1),
the storage unit (<NUM>) stores information on the longest position (R1), and
the control unit (<NUM>) controls, based on the information on the longest position (R1) stored in the storage unit (<NUM>), a supply of the metal pipe material (<NUM>) to the forming apparatus (<NUM>) by the supply device (<NUM>) such that the welded portion (14b) is not located on a straight line connecting the longest position (R1) and the center of the metal pipe material (<NUM>).