JP2006205275A - Method of manufacturing assembly and assembling assisting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an assembly and an assembling assisting device, for surely performing positioning and fixing work of parts, even if a flange part of the excessive size is not formed in the parts. <P>SOLUTION: Welding work is started by operating a laser welding gun 6 in a state of bringing a laminated part of the parts 1 and 2 into close contact with each other, by reducing pressure in a fuel tank 2 more than atmospheric pressure, by operating a sucker 10 by combining the parts 1 and 2. Since the assembling assisting device such as a clamp and a vice is not required, an excessive overhang of flanges 1a and 2a is eliminated, and generation of a flaw and deformation of a surface caused by sandwiching the parts 1 and 2, are also prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an improved assembly manufacturing method and an assembly assisting device.

  In general, welding or the like is known as a method of manufacturing an assembly that forms an assembly having a hollow inside. In addition, as a technique to maintain the positioning state by combining multiple parts while fixing work such as welding is performed, the part is fixed by holding the flange part of the part with an assembly assist device such as a clamp or vise. The method to do is common. However, it is necessary to prevent the clamp and vice from interfering with the end effector of the fixing means such as a welding gun. The movement path of the end effector is complicated, and the operation instruction of the movement path and the editing operation of the NC program are not performed. There are disadvantages such as complications. In addition, since it is necessary to securely hold the flange portion of the part with a clamp, a vise or the like, the overhang of the flange portion has to be increased, resulting in an adverse effect that the assembly such as the fuel tank becomes bulky as a whole.

  Therefore, several positioning methods and fixing methods have already been proposed in order to reduce such harmful effects.

  For example, unevenness is formed inside and outside the opening of a semi-container-like part formed in two parts to form a fuel tank, and the welding operation is performed while securing the positioning state by fitting these unevennesses. A method for manufacturing a fuel tank is disclosed as Patent Document 1. However, when such a manufacturing method is applied, a special processing step for forming irregularities inside and outside the opening is necessary, and when combining the parts, the opening needs to be elastically deformed. There is a drawback that the object of welding or the like is limited to those that are easily elastically deformed.

  In addition, a tapered welded joint is provided only at one opening of the half-container-shaped part of the two-part configuration, and the welding operation is performed after positioning the two half-container parts using the tapered surface of this joint. However, there is a possibility that an error may occur in the final assembly accuracy because the amount of joint entry may vary depending on the part, and an undercut is formed. Since the tapered welded joint must be provided in the opening portion, there is a disadvantage that a special processing step for forming the refracting portion is required as described above.

  In particular, when welding is used as the fixing means, the low melting point galvanized plating applied to the surface of the parts as a rust inhibitor may evaporate momentarily and form a blow hole on the joint surface. In order to prevent this, for example, as disclosed in Patent Document 3, it is necessary to provide a specially shaped relief or gas vent in the flange portion to be joined, which causes a problem that the processing of the flange portion becomes complicated.

JP-A-8-323487 (paragraph number 0020) JP-A-5-273 (paragraph 0009) JP-A-9-155575 (FIGS. 3 and 4)

  Therefore, an object of the present invention is to improve the inconveniences of the prior art, there is no fear that an assembly assisting device such as a clamp or a vise interferes with an end effector of a fixing means, and an excessively large flange portion is provided on a part. The parts can be positioned and fixed without any formation or special concavo-convex processing or refraction processing, and even if welding is used as a fixing means, An object of the present invention is to provide an assembly manufacturing method and an assembly assisting device in which blow holes are not easily generated.

The assembly manufacturing method according to the present invention is a method for manufacturing an assembly in which a plurality of parts are combined and fixed to form an assembly having a hollow inside.
In a state where the plurality of parts are combined and sealed, the pressure in the assembly is made lower than the external pressure, thereby bringing the mating portions of the plurality of parts into close contact, and then fixing the mating portions. It has a characteristic configuration.

Since the pressure inside the assembly is lower than the external pressure in a state where the parts are combined and sealed, the mating parts of the parts are brought into close contact, the parts are positioned and fixed, and then the mating parts are fixed. , Assembly assistance devices such as clamps and vices are not required.
Therefore, there is no concern that the clamp or vise will interfere with the end effector of the fixing means such as a welding gun, and the end effector's movement path can be matched with the part fitting part, that is, the contour of the part. The teaching operation of the moving path of the effector and the NC program editing work are facilitated.
In addition, there is no need to hold the parts from the outside with clamps or vise, so there is no need to form a special flange for positioning and fixing at the mating part of the parts, and excessive overhang of the flange is eliminated. In addition, the occurrence of scratches and deformation of the part surface due to the holding of the part, and the troublesomeness of attaching and detaching work such as clamp and vise are also eliminated, and the complicated shape that is difficult to hold by normal clamp or vise etc. It can cope with the sticking of parts.
In addition, since the mating part of the parts can be pressed and fixed with a uniform force, it is possible to obtain a uniform and uniform fixing result over the entire mating part by fixing means such as welding, welding or adhesion. It becomes.
Also, unlike positioning and fixing by concave / convex fitting, there is no need for special processing steps to form irregularities and refracted parts in parts, and positioning and fixing are ensured even for parts that are difficult to deform elastically. It can be carried out.
The present invention is particularly suitable for an assembly that becomes a substantially sealed container in a state in which a plurality of parts are combined, for example, a container such as a fuel tank of an automobile, but is opened in a state in which a plurality of parts are combined. Even if the assembly is formed, the opening can be easily applied by sealing the opening with another sealing member.

  More preferably, the pressure in the assembly is measured, and the pressure in the assembly is controlled to a substantially constant pressure within a range in which the assembly does not collapse based on the measured value.

Not all of the mating parts of the parts are fixed instantaneously by fixing means such as welding, welding or adhesion, but the pressure inside the assembly is lower than the external pressure until the fixing operation is completed. By maintaining a constant pressure, the crimping force of the mating part can be made constant at any point in time series after the start of the fixing operation, in other words, at any fixing point, and uniform under a certain condition. Can be obtained.
In particular, when fixing work such as welding is continuously performed along the path of the mating part, the sealing property of the mating part is low at the initial stage of starting the fixing work, and the sealing property of the mating part is high as the fixing work proceeds. Therefore, if the pressure inside the assembly is reduced using a suction machine or the like, the pressure inside the assembly may become excessively low as the fixing operation proceeds. It is desirable to control the pressure in the assembly so that the pressure is substantially constant.

  Further, after the mating portion of the assembly is fixed, it is possible to determine the fixing state based on the presence or absence of the time-series change in the pressure value inside the assembly or the degree of the change. .

Since the sealing of the assembly should be complete or almost complete at the stage where the mating portion is fixed, the pressure is determined based on whether or not the pressure value inside the assembly changes over time or the degree of change. It is possible to easily identify the presence or absence of leakage, more specifically, whether the fixing operation has been properly completed or whether the fixing operation has been completed while leaving a defective portion.
Accordingly, it is possible to reliably detect defective fixing that is difficult to visually check, and it is not necessary to provide a special inspection process, so that the work process as a whole can be simplified.

  More specifically, an opening is provided in the assembly, and in a state where the plurality of parts are combined and sealed, a fluid that fills the inside of the assembly is sucked from the opening, so that the pressure in the assembly is externally applied. It is desirable to make it lower than the pressure.

  Since the assembly itself is used as a pressure vessel to reduce the pressure in the assembly so that the pressure in the assembly is lower than the external pressure, there is no need to provide a special preload chamber, and a simple structure and Parts can be positioned and fixed accurately in a small space. From the technical point of view of cost effectiveness, it is also possible to obtain the same effect by placing an assembly that is sealed in combination at atmospheric pressure into the preload chamber.

  Further, flanges may be formed at the mating portions of the plurality of parts, and the flanges may be overlapped and fixed together.

By providing the flange, it is possible to increase the bonding area of the mating portion by increasing the bonding area of the mating portion.
However, since this flange is not intended for positioning or clamping by clamping, the size of the overhang should be within the range required from the viewpoint of securing the degree of adhesion and securing the fixing strength.

  Furthermore, it is possible to form this flange toward the outside of the assembly and fix the mating surface of the flange.

  Since the fixing work such as welding can be performed by positively using the surface of the flange serving as the mating portion, the fixing strength is improved, and the parts can be easily aligned.

  Alternatively, the flange may be formed toward the inside of the assembly, and after the flanges are aligned, the mating portions of the plurality of parts may be fixed from the outside of the assembly.

  Since the flange does not protrude outside the assembly, the problem that the assembly is bulky is solved. In addition, when the mounting space for mounting the assembly is limited, the body part of the assembly, which is a functional component, can be enlarged compared to the case where the flange is formed facing the outside of the assembly under the same limitation. It is.

  In particular, when the parts are made of a weldable material, it is desirable to use welding as a means for fixing.

  Compared to other fixing means such as bonding, it is possible to shorten the overall time required for fixing work including curing.

  When welding is used as the fixing means, it is desirable to keep sucking the fluid in the assembly during welding of the mating portion of the assembly.

  Since the low melting point zinc plating evaporated from the surface of the part is sucked together with the fluid, the occurrence of blowholes can be prevented without forming a special escape or gas vent in the part.

  Further, when the assembly is a fuel tank, it is essential to provide a fuel pump mounting port because of the structure. Therefore, the fuel pump mounting port is used as an opening for sucking fluid. To.

As a result, a special processing step for providing an opening for sucking the fluid becomes unnecessary, and productivity is improved.
As described above, the present invention is particularly suitable for an assembly that becomes a substantially sealed container in a state where a plurality of parts are combined, for example, a container such as a fuel tank of an automobile, but the combination of a plurality of parts. Even in an assembly in which an opening is formed in a closed state, the opening can be easily applied by sealing the opening with another sealing member. If an opening for sucking fluid is formed in the assembly itself by additional machining, the original function of the assembly may be reduced, or post-processing may be required to fill the opening. In the case of an assembly in which an opening is formed in a state where parts are combined, it is preferable to provide an opening in another sealing member that seals the opening so as to suck fluid.

The assembly assisting device of the present invention is an assembly assisting device used in the manufacture of an assembly in which a plurality of parts are combined and fixed to form an assembly having a hollow inside, in order to achieve the same problem as described above. In particular,
A suction machine that sucks fluid in the assembly that is sealed by combining the plurality of parts, a pressure measuring instrument that measures the pressure inside the assembly, an opening formed in the assembly, and the suction machine The pressure inside the assembly is preset based on the measurement result of the suction measuring valve provided on the connecting pipe line, the relief valve connected to the opening formed in the assembly, and the pressure measuring device. The suction control valve and the valve controller for driving and controlling the relief valve so that the pressure is within the range are provided.

This assembly assisting device is an assembly assisting device used for positioning and fixing of parts when a plurality of parts are combined and fixed.
In the use, first, after a plurality of parts are combined, a valve controller that drives and controls the suction adjustment valve and the relief valve and a suction machine that sucks the fluid in the assembly are operated.
Then, the suction machine sucks the fluid in the assembly and gradually reduces the pressure inside the assembly, and presses each part together while maintaining the mutual position of the parts that make up the assembly appropriately. Fix it.
During this time, the valve controller sequentially reads the measurement results detected by the pressure measuring instrument that measures the pressure inside the assembly, and determines whether or not the pressure inside the assembly is within a preset range. The opening / closing state or opening degree of the suction adjustment valve and the relief valve are adjusted so that the pressure inside the assembly becomes a pressure within a preset range.
As a specific control mode, for example, the operation amount of the suction adjustment valve is adjusted by PID control (proportional operation, integral operation, differential operation) based on the deviation between the measurement result by the pressure measuring instrument and a preset target pressure. Only when the pressure inside the assembly is suddenly reduced for some reason, it is desirable to open the relief valve and introduce external fluid into the assembly to prevent the assembly from collapsing.
As already mentioned, the pressure in the assembly is made lower than the external pressure in a state where the parts are combined and sealed, so that the parts are aligned and fixed so that the parts are positioned and fixed. No need for assembly aids such as welding and vise, and there is no concern that clamps or vice will interfere with the end effector of the fixing means such as a welding gun. The shape can be matched, and the teaching operation of the movement path of the end effector and the editing operation of the NC program are facilitated.
In addition, there is no need to hold the part from the outside with a clamp or vise, so there is no need to form a special flange part for positioning and fixing at the mating part of the part, eliminating excessive overhang of the flange part. In addition, the occurrence of scratches and deformation of the part surface due to the holding of the part, and the troublesomeness of attaching and detaching work such as clamp and vise are also eliminated, and the complicated shape that is difficult to hold by normal clamp or vise etc. It can cope with the sticking of parts.
In addition, since the mating part of the parts can be pressed and fixed with a uniform force, fixing work such as welding, welding or bonding can be performed on the entire mating part while the assembly assist device is operating. It is possible to obtain a uniform fixing result evenly.
Also, unlike positioning and fixing by concave / convex fitting, there is no need for a special processing step to form concave / convex or refracted parts, and positioning and fixing are ensured even for parts that are difficult to deform elastically. Can do.
Moreover, since the pressure in the assembly is maintained at a substantially constant pressure lower than the external pressure until the fixing operation is completed, any fixing time, in other words, any fixing time. The crimping force of the mating portion can be made constant at the location, and a uniform fixing result can be obtained under certain conditions.
In addition, since the assembly itself is used as a pressure vessel to reduce the pressure in the assembly so that the pressure in the assembly is lower than the external pressure, there is no need to provide a special preload chamber, Parts can be positioned and fixed accurately with a structure and a small space.
Furthermore, when welding is used as a fixing means, the low melting point zinc plating evaporated from the surface of the part is sucked together with the fluid, so that a blowhole can be generated without forming a special escape or gas vent. Can be prevented.

The assembly manufacturing method and the assembly assisting device according to the present invention position and fix the parts together by bringing the mating parts into close contact with each other by lowering the pressure in the assembly from the external pressure while the parts are combined and sealed. Therefore, there is no need for assembly assist devices such as clamps and vise, and there is no fear that the clamps or vice will interfere with the end effector of the fixing means such as a welding gun. The path can be made to coincide with the matching part of the part, that is, the contour shape of the part, and the teaching operation of the end effector moving path and the editing operation of the NC program are facilitated.
In addition, there is no need to hold the part from the outside with a clamp or vise, so there is no need to form a special flange part for positioning and fixing at the mating part of the part, eliminating excessive overhang of the flange part. In addition, the occurrence of scratches and deformation of the part surface due to the holding of the part, and the troublesomeness of attaching and detaching work such as clamp and vise are also eliminated, and the complicated shape that is difficult to hold by normal clamp or vise etc. It can cope with the sticking of parts.
In addition, since the mating part of the parts can be pressed and fixed with a uniform force, fixing work such as welding, welding, or adhesion can be performed to achieve a uniform and uniform fixing result over the entire mating part. Obtainable.
Also, unlike positioning and fixing by concave / convex fitting, there is no need for a special processing step to form concave / convex or refracted parts, and positioning and fixing are ensured even for parts that are difficult to deform elastically. Can do.

  Furthermore, since the pressure in the assembly is maintained at a substantially constant pressure lower than the external pressure until the fixing operation is completed, in other words, at any point in time series after the start of the fixing operation. For example, the pressure-bonding force of the mating portion can be made constant at any fixing location, and a uniform fixing result can be obtained under certain conditions.

  In addition, after fixing the mating part of the assembly, the fixing condition is judged based on whether or not the pressure value inside the assembly changes over time, or the degree of change. Since defects can be detected reliably and there is no need to provide a special inspection process, the work process as a whole can be simplified.

  In addition, since the assembly itself is used as a pressure vessel to reduce the pressure in the assembly so that the pressure in the assembly is lower than the external pressure, there is no need to provide a special preload chamber, Parts can be positioned and fixed accurately with a structure and a small space.

  Further, by forming flanges at the mating portions of a plurality of parts and overlapping and fixing the flanges to each other, the joining area of the mating portions can be increased and the adhesion of the mating portions can be increased.

  In particular, the fixing strength is improved by forming the flange toward the outside of the assembly and fixing the mating surfaces of the flange, and the parts can be easily aligned.

  Also, if the flange is formed facing the inside of the assembly and the flanges are aligned to secure the mating part of the part from the outside of the assembly, the flange will not protrude outside the assembly. The problem that the solid is bulky is solved. Further, when the mounting space for attaching the assembly is limited, the main body portion of the assembly, which is a functional component, can be made larger than when the flange is formed facing the outside of the assembly.

  When the parts are made of a weldable material, it is desirable to use welding as a means for fixing, and the overall time required for fixing work including curing compared to other fixing means such as adhesion. Can be shortened.

  Furthermore, by continuing to suck the fluid in the assembly during welding of the mating part, the low melting point zinc plating evaporated from the surface of the part can be sucked together with the fluid, so special escape and gas vents are formed in the part. Even without this, the occurrence of blowholes can be prevented.

  In addition, when the assembly is a fuel tank, it is essential to provide a fuel pump mounting port because of the structure. Therefore, the fuel pump mounting port should be used as an opening for sucking fluid. Thus, a special processing step for providing an opening for sucking the fluid is unnecessary, and the productivity is improved.

  Next, the best mode for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a conceptual view schematically showing an assembly assisting device used in carrying out an assembly manufacturing method according to the present invention and an overall system required for manufacturing the assembly.

  This embodiment is based on the premise that the fuel tank 3 for an automobile as an assembly is manufactured by combining the half-container-like parts 1 and 2 having a two-part configuration and fixing them by laser welding. Although not visible as a blind spot in FIG. 1, a fuel pump attachment port 4, which is an opening for connecting to the fuel pump of the vehicle, is provided on the lower surface side of the part 2 located below, for example, FIG. As shown in FIG. 1, the part 2 is provided integrally.

  Flange 1a, 2a integrally formed toward the outside is integrally provided at each mating portion of the semi-container-like parts 1, 2 and the fuel tank 3 is mounted on the vehicle at the four corners of the flanges 1a, 2a. Bolt through holes 5 that are necessary for this are drilled in advance. However, in this embodiment, the flanges 1a and 2a are only used as welding surfaces for fixing, and it is not necessary to hold the flanges 1a and 2a with clamps to fix the parts 1 and 2, so that the bolt through holes Except for the portion 5, the amount of overhang may be slight.

  The semi-container-like parts 1 and 2 are formed of a metal material that can be laser-welded, and the surface thereof is subjected to low melting point galvanization or the like for rust prevention.

  A laser welding gun 6 used for welding is attached as an end effector to the tip of an articulated industrial robot 8 that is driven and controlled by a numerical control device 7, and a laser for welding work in response to a command from the numerical control device 7. Output ON / OFF and assist gas ejection ON / OFF are controlled.

  The industrial robot 8 is driven and controlled in accordance with a machining program stored in the numerical control device 7 in the same manner as in the past, and an arm along the welding path generated based on the teaching operation, CAD data, or the like. The laser welding gun 6 attached to the tip is moved.

  The main parts of the assembly assisting device 9 in this embodiment are formed in the fuel tank 3 and the suction machine 10 for sucking the fluid in the fuel tank 3, that is, air in a state where the semi-container parts 1 and 2 are combined and sealed. Provided on the pipe 11 connecting the fuel pump mounting port 4 and the suction machine 10, and on the outside air inflow pipe 13 connected to the fuel pump mounting port 4 formed in the fuel tank 3. And the valve controller 15 that controls the opening and closing of the suction adjustment valve 12 and the relief valve 14 so that the pressure in the fuel tank 3 becomes a pressure within a preset range.

  FIG. 2B shows the appearance of the attachment 16 used to connect the pipe 11, the outside air inflow pipe 13, and the pressure detection extension pipe 17 to the fuel pump attachment port 4 formed in the fuel tank 3. The perspective view shown and FIG.2 (c) are the sectional drawings. The attachment 16 includes an attachment main body 16 a having nipples 18, 19, and 20 for connecting the pipe line 11, the outside air inflow pipe line 13, and the extension pipe 17, and a connection for attaching the attachment main body 16 a to the fuel pump attachment port 4. The ring 16b includes an O-ring 21 sandwiched between the outer peripheral flange of the attachment main body 16a and the inner peripheral flange of the connection ring 16b, thereby preventing air leakage when the attachment 16 is attached to the fuel pump attachment port 4. It has come to be.

  The attachment 16 is attached to the fuel tank 3 by screwing the connection ring 16b to the fuel pump mounting port 4 of the fuel tank 3, and the connection ring 16b is attached to the fuel tank 3 to be assembled. Specifications, specifically, several types of inner diameters are prepared in advance according to the specifications of the diameter of the fuel pump mounting port 4, and the connection ring 16b can be freely replaced according to the specifications of the fuel pump mounting port 4 It can be done.

  The other end of the extension pipe 17 connected to the nipple 20 is connected to a valve controller 15 that also serves as a pressure measuring instrument, and the extension sensor 17 (see FIG. 4) that is a pressure measuring instrument built in the valve controller 15 is used. The internal pressure of the fuel tank 3, that is, the internal pressure of the fuel tank 3 is detected.

  The work table 23 for holding the positioning state by combining the semi-container-like parts 1 and 2 is a table with legs, and the upper surface thereof is formed in the flanges 1a and 2a of the parts 1 and 2 Screw holes 25 for attaching the positioning pins 24 to enter the bolt through holes 5 and prevent the positional displacement of the parts 1 and 2 are provided in a matrix as shown in FIG. As shown in FIG. 3B, the positioning pin 24 is a cylindrical body having a conical taper 24a at the tip, and has a height from the upper surface of the work table 23 to the flanges 1a and 2a of the parts 1 and 2. A large-diameter portion 24b for restriction and a male screw portion 24c screwed into the screw hole 25 are provided. Since many screw holes 25 are provided on the upper surface of the work table 23, the fuel tank 3 having various specifications is selected by selecting the screw holes 25 into which the positioning pins 24 are screwed according to the dimensions of the fuel tank 3. Can deal with. A hole 26 drilled in the central portion of the work table 23 is for passing the pipe line 11, the outside air inflow pipe line 13, and the extension pipe 17 extending from the attachment 16 connected to the fuel pump mounting port 4. . In addition, if the large-diameter portion 24b of the positioning pin 24 is formed to be long so that a sufficiently large gap is formed between the upper surface of the work table 23 and the lower surface of the semi-container-like part 2, this It is also possible to let the pipe 11, the outside air inflow pipe 13, and the extension pipe 17 escape to the side through the gap.

  As shown in FIG. 4, a main part of the valve controller 15 is used for a microprocessor 27 (hereinafter simply referred to as a CPU 27) as a calculation means, a ROM 28 storing a control program for the CPU 27, and a temporary storage of calculation data. The signals from the start switch 30 and the emergency stop switch 31 arranged on the front panel of the valve controller 15 are read into the CPU 27 via the input / output circuit 32, while the display unit 33 receives the signals from the CPU 27. Various messages are displayed according to the commands.

  Further, the internal pressure of the extension pipe 17 measured by the pressure sensor 22 which is a pressure measuring instrument, that is, the internal pressure of the fuel tank 3 is read into the CPU 27 via the AD converter 34 and the input / output interface 35, and ON / OFF, the opening degree of the suction adjustment valve 12 and the opening / closing of the relief valve 14 are controlled by the CPU 27 via the respective drivers 36, 37, 38 and the input / output interface 35.

  The numerical control device 7 that drives and controls the industrial robot 8 can transmit information to and from the CPU 27 via the input / output interface 35.

  5 and 6 are flowcharts showing an outline of the pressure control process executed by the CPU 27 constituting the main part of the valve controller 15.

  Next, with reference to FIG. 5 and FIG. 6, the manufacturing procedure of the assembly and the overall operation of the assembly assisting device 9 in the present embodiment will be specifically described.

  First, as a preparatory work for manufacturing the fuel tank 3, the worker places a position corresponding to the shape and dimensions of the semi-container-like parts 1 and 2 from among the numerous screw holes 25 on the work table 23. A certain screw hole 25 is selected, and the male screw portion 24c of the positioning pin 24 is screwed into these screw holes 25 and attached.

Next, the operator carries in the semi-container-shaped part 2 constituting a part of the fuel tank 3, passes each of the bolt through holes 5 formed in the four corners of the flange 2 a through the tip of the positioning pin 24, The part 2 is placed on the work table 23 so that the four corners of the flange 2a are supported by the stepped portion of the large diameter portion 24b of the positioning pin 24.
Further, in the same manner, the semi-container-like part 1 is carried in, the bolt through holes 5 drilled at the four corners of the flange 1a are passed through the tip of the positioning pin 24, and the flange 1a is overlapped with the flange 2a. Then, by placing the part 1 on the part 2, the semi-container-like part 1 and the part 2 are combined to perform relative positioning between them, and the part 1 and the part 2 are substantially sealed.

  Then, the fuel tank comprising the parts 1 and 2 in the temporarily assembled state is formed by letting the hole 26 from the lower surface side of the work table 23 and screwing the connection attachment 16 into the fuel pump mounting port 4 of the part 2. The suction machine 10 and the valve controller 15 are connected to 3.

  Here, when an opening other than the fuel pump attachment port 4, such as a fuel inlet, has already been drilled in part 1 or part 2, a sealing member such as a fuel cap is attached to this opening. The fuel tank 3 needs to be substantially sealed.

  Next, when the operator operates the start switch 30 of the valve controller 15, the CPU 27 of the valve controller 15 detects the operation of the start switch 30 in the determination process of step S1 in FIG. 5, and the pressure control shown in FIG. 5 and FIG. Start automatic processing.

The CPU 27 that has detected the input of the start command first initializes the decompression completion flag F, the deviation value storage registers R _{1 to} R _n and the register search index i to 0 (steps S 2 to S 4), and opens the relief valve. The initial value 0 (%) is set in the degree adjustment register _DL , the relief valve 14 is fully closed (step S5), and the operation of the suction machine 10 is started (step S6).

The decompression completion flag F is such that the internal pressure of the fuel tank 3 that is an assembly is lower than the atmospheric pressure that is an external pressure, and the flanges 1a and 2a of the parts 1 and 2 can be brought into close contact with a pressure contact force suitable for welding work. This flag is set when it falls to
In this embodiment, to prevent the collapse of the fuel tank 3 is an assembled body, and, on the need to ensure a state suitable for welding a contact pressure of the flange 1a and the part 2 of the flange 2a of the part 1, P ₀ ( For example, -8 Kpa <atmospheric pressure) is set as a target value for pressure control, and an upper limit set pressure P _max (for example, −7 Kpa <atmospheric pressure) and a lower limit set pressure P _min (for example, −9 Kpa <atmospheric pressure) are preset ranges. As the internal pressure, the opening degree which is the operation amount of the suction adjustment valve 12 is controlled so that the actual pressure P in the fuel tank 3 falls within the range of P _{min to} P _max , and the actual pressure P in the fuel tank 3 is when the fuel tank 3 rapidly decreases for some reason is below the front of the limit limit P _lim to crush _(e.g. -12Kpa), the fuel tank 3 to the relief valve 14 is completely opened Actual pressure P in the fuel tank 3 so as to prevent a decrease in it than by drawing outside air.
The deviation value storage registers R _{1 to} R _n are used for calculating an integral term in the PID control of pressure. In these registers R _{1 to} R _n , the values of deviations P ₀ -P between the actual pressure P in the fuel tank 3 measured by the pressure sensor 22 and the preset pressure control target value P ₀ are recently stored. Are stored over n measurement cycles.
The register search index i is an index for specifying the deviation value storage register R _i that stores the value of the deviation P ₀ -P obtained in the new measurement cycle.

The CPU 27 that has started the operation of the suction machine 10 as described above then reads the actual pressure P in the fuel tank 3 via the pressure sensor 22 (step S7), and this value is stored in the final actual pressure storage register _RL. (Step S8), the value of the register search index i is incremented by 1 (step S9), and it is determined whether or not the current value of the index i exceeds the total number n of deviation value storage registers (step S10). If it does not exceed, the value of the index i is held as it is, whereas if it exceeds, the value 1 is set again to the index i (step S11).
Since deviation value storage register capable of storing the value of the deviation P ₀ -P is the n-number of R ₁ to R _n, the deviation should store the value of the deviation P ₀ -P determined in a new measurement cycle The value of the index i specifying the value storage register R _i must also be limited to an integer in the range of 1 to n.

Next, the CPU 27 determines whether or not the current value of the register search index i is 1 (step S12). If the current value of the index i is 1, the deviation P ₀ −P in the previous measurement cycle is determined. N is set to the register search index j for specifying the deviation value storage register storing the value of (step S13), and if the current value of the index i is any value other than 1, that is, any one of 2 to n, 1 It sets a value corresponding to i-1 to register the search index j specifying the deviation value storage register for storing a value of the deviation P ₀ -P in the measurement period of the previous cycle (step S14).
This is pre-processing for realizing the calculation of the differential term in the PID control of the pressure. In this embodiment, the differential period is obtained by subtracting the value of the deviation P ₀ -P in the previous measurement period from the deviation P ₀ -P in the current measurement period, with the measurement period as the differential time. required differential term by the current value is to reduce the values of clogging deviation value storage register R _i-1 of the deviation value storage register R _j from the deviation value storage register R _i when in the range of 2~n of the index i If the current value of the index i is 1, the differential term is obtained by subtracting the value of the deviation value storage register R _j , that is, the value of the deviation value storage register R _n from the deviation value storage register R _{i = 1.} Desired.

Next, the CPU 27 calculates the deviation P ₀ -P in the current measurement cycle based on the preset target value P ₀ of pressure control and the value of the actual pressure P read in step S7 in the current measurement cycle. This value is obtained and stored in the deviation value storage register R _i specified by the current value of the register search index i (step S15).
Also, make substantial integration processing by adding all the values of the deviation value storage register _{R i} of i = 1 to n, obtains the integral term sigma _P in the PID control (step S16).

Then, CPU 27 may register the search by the index i from the value of the deviation value storage register R _i specified register search index j by subtracting the value of the deviation value storage register R _j specified for one measurement cycle to be the derivative term variation amount of the deviation (R i _{-R j)} the determined, the deviation of the current measurement period determined in the processing of the values sigma _P and S15 of the integral term obtained in the processing of the value of the derivative term and the step S16 R _i Furthermore, y = K _P · R _i + (K _P / n) · Σ _P + K _P · (R _i −) based on the number of measurements n corresponding to the integration time and a preset proportional gain K _P. R _j ) is executed, and the opening y (%) of the suction adjustment valve 12 corresponding to the operation amount of the PID control is obtained (step S17).
It should be noted that until the integration time is reached after the processes related to reading of the actual pressure P (step S7), calculation of the deviation P ₀ -P and storage in the deviation value storage register (step S15) are repeated n times or more. Therefore, there is a deviation value storage register that does not store the deviation, and the influence of the integral term (K _P / n) · Σ _P on the manipulated variable y (%) is reduced. This is not a real problem because the time is fast enough.

Next, the CPU 27 determines whether or not the opening y (%) of the suction adjustment valve 12 exceeds 100 (%) (step S18), and if not, sucks the value of y (%) as it is. The adjustment valve opening adjustment register _DV is set to set the opening of the suction adjustment valve 12 to y (%) (step S20). If it exceeds, the value of y (%) is set to 100 (%). And the suction adjustment valve opening adjustment register _DV is set, and the suction adjustment valve 12 is fully opened (step S19).
Since at the stage immediately after start of the assembly aid device 9 deviation between the target value P ₀ the actual pressure P is large, so that the suction operation by the suction unit 10 a suction control valve 12 as fully opened is performed.

Then, the CPU 27 determines whether the value of the actual pressure P in the fuel tank 3 read in the process of step S7 in the current measurement cycle is within a range of P _{min to} P _max that is a pressure within a preset range. If it is not within this range, it is further determined whether or not the actual pressure P is below a limit value P _lim that may cause the tank 3 to be collapsed (step S25). ).

Since the actual pressure P does not fall below P _max (for example, −7 Kpa) or P _lim (for example, −12 Kpa) at the moment when the operation of the suction device 10 is started, at least at the stage immediately after the start of the assembly assisting device 9, the step the determination result of S21 and step S25 are both false, and consequently, the value of the relief valve opening control register D _L is held at 0, the fully closed state of the relief valve 14 is maintained (step S26).

  Next, the CPU 27 determines whether or not a welding completion signal is input from the numerical controller 7 (step S28). At this time, the drive control of the industrial robot 8 and the laser welding gun 6 by the numerical controller 7 is not yet performed. Since it has not started and no welding completion signal is input from the numerical controller 7, the determination result in step S28 is necessarily false.

  Therefore, the CPU 27 determines whether or not the signal from the emergency stop switch 31 provided on the front panel of the valve controller 15 is input (step S37). If the operation of the emergency stop switch 31 is not detected, the CPU 27 again. Returning to the process of step S7, the same process as described above is repeatedly executed.

In this way, by repeating the processing of step S7 to step S21, step S25 to step S26, step S28, and step S37 while maintaining the fully closed state of the relief valve 14, the latest n measurement cycles are performed. The opening adjustment of the suction adjustment valve 12 is automatically performed by PID control using the value of the deviation P ₀ -P obtained in (1). Then, the actual pressure P in the fuel tank 3 gradually decreases from the initial atmospheric pressure to the pressure control target value P ₀ (for example, −8 Kpa <atmospheric pressure).

Further, in the case where the value of the actual pressure P is below the limit limit P _lim there is a risk of crushing of the tank 3 is any trouble during this time, means the full open of the relief valve 14 to the relief valve opening control register D _L 100 Since (%) is set and the relief valve 14 is automatically opened (step S25, step S27), the collapse of the fuel tank 3 is reliably prevented under any circumstances.
Further, it is possible to forcibly stop the operation of the assembly assisting device 9 by operating the emergency stop switch 31 at the operator's intention regardless of whether the welding operation is started or the welding operation is being performed. (Step S37). Its case, the CPU27 opens the relief valve 14 is set 100 (%) in the relief valve opening control register _{D L,} sets 0 (%) to the suction control valve opening control register _{D V} The suction adjustment valve 12 is closed (steps S38 and S39), and the operation of the suction machine 10 is stopped and an abnormality detection signal is output to the numerical controller 7 (steps S40 and S41). Since the suction adjustment valve 12 is closed prior to the stop of the suction machine 10, even if the suction machine 10 continues to move due to inertia, the internal pressure of the fuel tank 3 does not drop any more.

Further, while the processes of Step S7 to Step S21, Step S25 to Step S26, Step S28, and Step S37 are repeatedly executed, the actual pressure P in the fuel tank 3 is changed from the atmospheric pressure, which is the initial value, to the target value for pressure control. P _min (for example, −9 Kpa <atmospheric pressure) to P _max (for example, −7 Kpa <for example) is a pressure that falls smoothly toward P ₀ (for example, −8 Kpa <atmospheric pressure) and the actual pressure P is within a preset range. When the pressure falls within the range of (atmospheric pressure), the determination result in step S21 is true, and the CPU 27 confirms that the flange 1a of the part 1 is pressed against the flange 2a of the part 2 with an appropriate force.

  In this case, the CPU 27 determines whether or not the decompression completion flag F is set (step S22), but at this time, the decompression completion flag F is not set, and the determination result of step S22 is false.

  Therefore, the CPU 27 outputs a preparation completion signal to the numerical control device 7, starts driving control of the industrial robot 8 and the laser welding gun 6 by the numerical control device 7, that is, welding work (step S23), and further, a decompression completion flag. By setting 1 to F, the fact that the welding operation has been started is stored by itself (step S24).

Next, the CPU 27 determines whether or not a welding completion signal is input from the numerical control device 7 (step S28), but the welding operation by the industrial robot 8 and the laser welding gun 6 has not been completed at this time. Since the welding completion signal is not input from the numerical controller 7, the determination result in step S28 is necessarily false.
Therefore, the CPU 27 further determines whether or not the signal from the emergency stop switch 31 is input (step S37). If the operation of the emergency stop switch 31 is not detected, the process returns to step S7 again. The processing operation similar to the above is repeatedly executed.

In this way, the processes of step S7 to step S22, step S28, and step S37 are repeatedly executed, so that suction by PID control using the value of the deviation P ₀ -P obtained in the latest n measurement cycles is performed. The opening degree of the adjustment valve 12 is automatically adjusted, and the actual pressure P in the fuel tank 3 during execution of the welding operation is automatically close to the pressure control target value P ₀ (for example, −8 Kpa <atmospheric pressure). Retained.

  During this time, the numerical controller 7 that has received the preparation completion signal from the CPU 27 drives and controls the industrial robot 8, moves the laser welding gun 6, which is an end effector, from the standby position to the welding start position, and operates the laser welding gun 6. The welding operation is performed while moving the tip of the laser welding gun 6 along the upper surface of the flange 1a.

  Since the air in the fuel tank 3 is continuously sucked during the welding operation, the low melting point zinc plating evaporated from the surfaces of the parts 1 and 2 can be sucked together with the air. The occurrence of blow holes can be prevented without forming the parts 1 and 2.

As the welding operation proceeds in this way and the flanges 1a and 2a that are the mating surfaces of the parts 1 and 2 are gradually fixed, the amount of outside air that enters the fuel tank 3 from the mating surfaces gradually decreases. However, since the opening of the suction adjustment valve 12 is automatically adjusted using PID control, the pressure in the fuel tank 3 is controlled regardless of the length of the welded portion, that is, regardless of the degree of sealing of the fuel tank 3. it can be continued welding operation and accurately held in the vicinity of the target value P ₀ of the. As a result, the pressure contact force of the flanges 1a and 2a where the laser is actually irradiated and welded is always substantially constant, and at any point in time series after the start of the welding operation, in other words, at any welding location. Thus, uniform welding results can be obtained under certain conditions.

Further, when the value of the actual pressure P at some trouble during welding is below the limit limit P _lim there is a risk of crushing of the tank 3, it means the full open of the relief valve 14 to the relief valve opening control register D _L Since 100 (%) is set and the relief valve 14 is immediately opened (step S25, step S27), even if some trouble occurs during the welding operation, the fuel tank 3 is reliably prevented from being crushed. Is done.

  Further, when an emergency stop of work is necessary for some reason, the operator forcibly stops the operation of the assembly assisting device 9 by operating the emergency stop switch 31 (steps S37 to S40). ). In this case, an abnormality detection signal is output from the CPU 27 to the numerical controller 7 (step S41), and the welding operation by the laser welding gun 6 is also automatically stopped by the processing on the numerical controller 7 side. The problem that the welding operation is inadvertently continued while the pressure contact force of the flanges 1a and 2a becomes insufficient due to the stop is solved, and the product yield can be improved.

  Finally, when the operation of one cycle by the industrial robot 8 and the laser welding gun 6 is completed and the welding operation that makes a round of the flanges 1a and 2a is completed, the operation of the laser welding gun 6 is performed under the drive control of the numerical controller 7. Is stopped, the laser welding gun 6 as an end effector is returned to the standby position again, and a welding completion signal is output from the numerical controller 7 to the valve controller 15.

The CPU 27 of the valve controller 15 detects the input of the welding completion signal in the determination process in step S28, sets both the relief valve opening adjustment register _DL and the suction adjustment valve opening adjustment register _DV to 0 (%) and reliefs. After the valve 14 and the suction adjustment valve 12 are fully closed and the fuel tank 3 is sealed (step S29), the operation of the suction machine 10 is stopped (step S30), and a preset standby time is set. The timer T is set and measurement of the elapsed time after completion of the welding operation is started (step S31).

When it is confirmed that the elapsed time after completion of the welding operation has reached the set standby time (step S32), the CPU 27 reads the actual pressure P in the fuel tank 3 again via the pressure sensor 22 (step S33). ) The difference between the pressure value stored in the final actual pressure storage register _RL , that is, the actual pressure _RL in the fuel tank 3 detected at the time of completion of the welding operation and the actual pressure P after the set standby time has elapsed. Is determined, and it is determined whether or not this deviation is within a preset range of allowable pressure fluctuation ε (step S34).

  If the deviation is within the range of ε, the CPU 27 performs welding over the flanges 1 a and 2 a without any time-series change in the pressure inside the fuel tank 3 after welding, that is, no air leakage in the fuel tank 3. Assuming that the work is being performed properly, a message indicating the normal end of welding is displayed on the display 33 (step S35), and if the deviation exceeds the range of ε, It is assumed that there is a time-series change in the pressure inside the fuel tank 3 after the completion of welding, that is, air leakage in the fuel tank 3, and there is a defective portion in the welding that goes around the flanges 1a and 2a. Is displayed (step S36), and the series of pressure control processes is terminated.

  Therefore, it is possible to reliably detect welding defects that are difficult to visually confirm by automatic processing, and it is not necessary to provide a special inspection process, so that the overall work process can be simplified.

  The pressure fluctuation allowable value ε used for determining the suitability of welding is experimentally determined in consideration of the temperature change of the fuel tank 3 after the welding operation is completed and the slight air leakage in the suction adjustment valve 12 and the relief valve 14. It is desirable.

  Since the state of the numerical control device 7, the industrial robot 8, and the assembly auxiliary device 9 including the position of the laser welding gun 6 has all returned to the initial state at the time of completion of the welding operation, the fuel tank 3 that has been welded is placed on the workpiece. By operating the start switch 30 of the valve controller 15 after removing the base 23 and attaching the new parts 2 and 1, the same welding operation as described above can be repeatedly performed.

  In this embodiment, the valve controller 15 is provided independently of the numerical control device 7. However, generally, the numerical control device 7 is not necessary for linear interpolation or circular interpolation of a machining path or posture control of an end effector. Since the drive control of each axis including processing and pulse distribution processing is executed as multitask processing, numerical values can be obtained by executing the processing as shown in FIGS. 5 and 6 as one of the multitask processing. It is also possible to give the control device 7 the function of the valve controller 15. In this case, the pressure sensor 22, the suction machine 10, the suction adjustment valve 12, and the relief valve 14 are connected to the input / output interface of the numerical controller 7 and are driven and controlled.

In addition, when welding is performed manually without using the industrial robot 8 or the numerical control device 7, preparation is completed in the display unit 33 in step S23 in the processing shown in FIGS. This message is displayed for a predetermined time.
In addition, an end switch is provided on the front panel of the valve controller 15, and a process for detecting whether or not the end switch is operated is performed instead of the process of step S28. When the operation of the end switch is detected, If the operation is not detected, the process proceeds to step S29.

  As described above, the case where laser welding is performed by providing the outward flanges 1a and 2a on the parts 1 and 2 has been shown as an example. However, as shown in FIG. , 2a, and the flanges 1a, 2a may be overlapped with each other by laser welding the joints of the flanges 1a, 2a from the outside of the fuel tank 3, as shown in FIG. 7 (b). In addition, the welding operation may be performed using both the deep fusion by laser welding and the brazing material 39. Since the flange does not protrude outside the fuel tank 3, the problem that the outer shape of the fuel tank 3 becomes unnecessarily bulky can be solved.

  As for pressure control, any control method including proportional control and proportional integral control can be applied in addition to PID control, and the duty ratio between the fully open time and the fully closed time of the suction adjustment valve 12 is also possible. It is also possible to simply adjust. When adjusting the duty ratio between the fully open time and the fully closed time, it is desirable that a pressure control valve or the like for preventing the overload of the suction machine 10 is provided in the suction machine 10.

As described above, in this embodiment, in a state in which the parts 1 and 2 are combined and sealed, the pressure in the fuel tank 3 is made lower than the atmospheric pressure that is the external pressure, so that The flanges 1a and 2a are closely contacted to position and fix the parts, and the mating surfaces of the flanges 1a and 2a are welded by laser welding from the upper surface side of the flange 1a. No equipment is required.
Therefore, there is no worry that the clamp, vise, etc. interfere with the laser welding gun 6 as an end effector, and the movement path of the laser welding gun 6 can be made to coincide with the mating part of parts 1 and 2, that is, the contour shape of parts 1 and 2. In addition, the teaching operation of the moving path of the laser welding gun 6 and the NC program editing operation in the numerical controller 7 are facilitated.

  In addition, since there is no need to hold parts 1 and 2 from the outside with a clamp or a vise, there is no need to form a large flange for positioning and fixing at the mating part of parts 1 and 2. Excessive overhang is eliminated, and the occurrence of scratches and deformation of the flanges 1a and 2a due to the gripping of parts 1 and 2 and the troublesomeness of attaching and detaching work such as clamps and vices are also eliminated. It is also possible to cope with the adhering of parts 1 and 2 having complicated shapes that are difficult to hold.

  Furthermore, since the flanges 1a and 2a, which are the mating parts of the parts 1 and 2, can be fixed by pressing with a uniform force, a uniform and uniform welding result can be obtained over the entire circumference of the flanges 1a and 2a. Can do.

  Also, unlike positioning and fixing by concave / convex fitting, a special processing step for forming concave / convex and refracted parts on parts 1 and 2 is unnecessary, and positioning is ensured even for parts that are difficult to deform elastically. And can be fixed.

This embodiment is particularly suitable for an assembly that becomes a substantially closed container in a state where the parts are combined, for example, containers such as the fuel tank 3 of an automobile, but is opened in a state where a plurality of parts are combined. Even if the assembly is formed, the above-mentioned technical idea can be easily applied by sealing the opening with another sealing member.
For example, even if an opening other than the fuel pump mounting port 4, for example, a fuel charging port or the like is already drilled in the part 1 or the part 2 constituting the fuel tank 3, a sealing member is provided in this opening, For example, as described above, the fuel tank 3 can be substantially sealed by attaching and sealing a fuel cap or the like.
Moreover, as an assembly in which an opening is formed in a state where a plurality of parts are combined, there is, for example, a door structure of an automobile manufactured by fixing an outer panel and an inner panel. In manufacturing such a door, an easily detachable sealing member that closes a gap between the inner and outer door panels (such as a gap for inserting glass) is provided, and an opening is provided in this member to provide a conduit 11 and an outside air inflow conduit 13. , By connecting the extension pipe 17, it is possible to use the same assembly assisting device 9 as in the embodiment of FIG. 1 (excluding the work table 23). Since this type of door structure does not necessarily require sealing of the joint between the inner and outer door panels, spot welding or the like can be used instead of laser welding or resistance welding that continuously welds the entire joint. It is. When spot welding is used, the sealed state of the inner and outer door panels after completion of welding is not necessarily guaranteed, but the value of allowable pressure fluctuation ε and the setting time of timer T that determine the suitability of welding according to the degree of air leakage are Since it is a set value until it gets tired, it is possible to determine the suitability of welding with a certain degree of accuracy by setting the allowable pressure fluctuation value ε large or setting the timer T short. It is.

It is also conceivable to use an adhering operation using an adhesive or the like for an assembly that cannot be welded.
In that case, after the adhesive is applied to the mating part of the part, the mating part of the part is brought into close contact, but the substantial fixing effect due to the adhesive occurs after the mating part of the part is brought into close contact. Because there is (in the first place, it does not function as an adhesive if the adhesive is completely cured before the parts are brought into close contact), and the act of adhering the mating part of the parts after applying the adhesive to the mating part of the parts However, it is not deviated from the gist of the present invention that “parts matching parts are brought into close contact with each other, and then the parts matching parts are fixed”.
When using an adhesive as a fixing means, the suction action of the suction machine 10 has an effect of preventing the adhesive from dripping to the outside of the part. It is.

It is the perspective view which simplified and showed about an example of the whole system required for manufacture of the assembly assistance apparatus and assembly which are utilized when implementing the manufacturing method of the assembly by this invention. FIG. 2A is a diagram showing an example of a specific configuration of an attachment used for connection between a fuel tank as an assembly and an assembly auxiliary device, and FIG. 2A is a cross-sectional view showing the structure of a fuel pump attachment port, FIG. 2 (b) is a perspective view showing the appearance of the attachment, and FIG. 2 (c) is a cross-sectional view showing the structure of the attachment. FIG. 3A is a plan view of a work table used for mounting and positioning of a fuel tank as an assembly, FIG. 3A is a plan view of the work table, and FIG. It is the perspective view which showed the structure of the positioning pin attached. It is the functional block diagram which showed the outline of the structure of the valve controller. It is the flowchart which showed the outline of the pressure control process performed by CPU which comprises the principal part of a valve controller. It is a continuation of the flowchart which showed the outline of the pressure control process. FIG. 7A is a cross-sectional view showing a welding mode when an inward flange is provided on a part, FIG. 7A shows a fixing method using only laser welding, and FIG. 7B shows laser welding and brazing material. It shows about the fixing method using together.

Explanation of symbols

1, 2 Parts 1a, 2a Flange 3 Fuel tank (assembly)
4 Fuel pump mounting port (opening)
5 Bolt through hole 6 Laser welding gun (end effector)
7 Numerical control device 8 Industrial robot 9 Assembly assist device 10 Suction machine 11 Pipe line 12 Suction adjustment valve 13 Outside air inflow line 14 Relief valve 15 Valve controller 16 Attachment 16a Attachment body 16b Connection ring 17 Extension pipes 18, 19, 20 Nipple 21 O-ring 22 Pressure sensor (pressure measuring instrument)
23 Work table 24 Positioning pin 24a Taper 24b Large diameter portion 24c Male thread portion 25 Screw hole 26 Hole 27 Microprocessor (CPU)
28 ROM
29 RAM
30 start switch 31 emergency stop switch 32 input / output circuit 33 display 34 AD converter 35 input / output interface 36, 37, 38 driver 39 brazing material

Claims (11)

In an assembly manufacturing method in which an assembly having a hollow inside is formed by combining and fixing a plurality of parts,
In a state where the plurality of parts are combined and sealed, the pressure in the assembly is made lower than the external pressure, thereby bringing the mating portions of the plurality of parts into close contact, and then fixing the mating portions. A method of manufacturing a featured assembly.   2. The assembly according to claim 1, wherein the pressure in the assembly is measured, and the pressure in the assembly is controlled to a substantially constant pressure within a range in which the assembly does not collapse based on the measured value. Solid manufacturing method.   The fixing state is determined based on the presence or absence of a time-series change in the pressure value inside the assembly or the degree of the change after fixing the mating portion of the assembly. Method for manufacturing the assembly.   In the state where the assembly is provided with an opening and the plurality of parts are combined and sealed, a fluid filling the inside of the assembly is sucked from the opening so that the pressure in the assembly is lower than the external pressure. The manufacturing method of the assembly as described in any one of Claims 1-3 characterized by the above-mentioned.   The manufacturing method of the assembly according to any one of claims 1 to 4, wherein a flange is formed at each of the mating portions of the plurality of parts, and the flanges are overlapped and fixed to each other.   6. The method of manufacturing an assembly according to claim 5, wherein the flange is formed toward the outside of the assembly, and a mating surface of the flange is fixed.   6. The assembly according to claim 5, wherein the flange is formed toward the inside of the assembly, and after the flanges are aligned, the mating portions of the plurality of parts are fixed from the outside of the assembly. Production method.   The method of manufacturing an assembly according to any one of claims 1 to 7, wherein the plurality of parts are made of a weldable material, and the fixing means is welding.   9. The method for manufacturing an assembly according to claim 8, wherein the fluid in the assembly is continuously sucked during welding of the mating portion of the assembly.   The method of manufacturing an assembly according to any one of claims 1 to 9, wherein the assembly is a fuel tank, and the opening is a fuel pump attachment port. An assembly auxiliary device used for manufacturing an assembly in which a hollow assembly is formed by combining and fixing a plurality of parts,
A suction machine that sucks fluid in the assembly that is sealed by combining the plurality of parts, a pressure measuring instrument that measures the pressure inside the assembly, an opening formed in the assembly, and the suction machine The pressure inside the assembly is preset based on the measurement result of the suction measuring valve provided on the connecting pipe line, the relief valve connected to the opening formed in the assembly, and the pressure measuring device. An assembly assisting device comprising: a valve controller that drives and controls the suction adjustment valve and the relief valve so that the pressure is within a range.

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