JP3907552B2 - Welding method and welding system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a welding method and a welding system for welding a fuel tank of a motorcycle, and more particularly to a welding method and a welding system that reduce the influence of thermal distortion caused by welding.
[0002]
[Prior art]
As shown in FIG. 15, a fuel tank 200 in a motorcycle is generally welded at the bottoms of an outer plate 202 and an inner plate 204. The outer plate 202 and the inner plate 204 are generally bent at their ends downward to form a flange portion 206, and the flange portion 206 is generally seam welded.
[0003]
Among motorcycles, a type in which the position of the steering wheel is high and the passenger operates with the upper body almost upright, so-called American type motorcycles, the aesthetics of the fuel tank 200 are particularly important. . In the fuel tank 200 that requires aesthetics in this way, it is not preferable that the welded flange portion 206 is exposed. Further, the center of gravity of the fuel tank is shifted upward by the height of the flange portion 206, which is inconvenient for lowering the center of gravity of the motorcycle.
[0004]
Furthermore, the oil storage capacity of the fuel tank 200 is limited due to the presence of the flange portion 206.
[0005]
As a fuel tank having a structure in which the flange portion formed by seam welding does not extend downward, a technique for bending the flange portion toward the inner side of the vehicle body has been proposed (see, for example, JP-A-10-76985). However, in this technique, a useless space exists above the flange portion, and the capacity of the fuel tank is limited.
[0006]
[Problems to be solved by the invention]
In order to manufacture a fuel tank having a structure without a flange portion, it is necessary for a skilled welder to perform welding by arc welding or the like. When performing automatic welding using a robot, the fuel tank, which is a workpiece, is firmly fixed, so there is no escape from thermal distortion, and cracks are likely to occur, resulting in poor yield. When a crack occurs, repair by a skilled welder is necessary.
[0007]
The present invention has been made in consideration of such problems. When welding a fuel tank of a motorcycle, welding that reduces the influence of thermal distortion caused by welding and suppresses the occurrence of cracks. It is an object to provide a method and a welding system.
[0008]
[Means for Solving the Problems]
A welding method according to the present invention is a welding method that includes one or a plurality of attachments, and welds the fuel tank using a plurality of opening / closing mechanisms that abut and separate the attachment from a fuel tank of a motorcycle. The step of holding the fuel tank by bringing the attachment into contact with the fuel tank by the opening / closing mechanism, and the welding point approaches when the welding point to be welded moves along the welding line And sequentially separating the attachment from the fuel tank by the opening / closing mechanism.
[0009]
In this way, when the welding point moves along the welding line, if the attachment is separated from the fuel tank in the order in which the welding point approaches, the influence of thermal distortion due to welding is reduced and cracking is suppressed. Can do.
[0010]
In this case, if the attachment holds the fuel tank via an elastic body, the influence of thermal distortion due to welding can be reduced even while the attachment is in contact with the fuel tank.
[0011]
The fuel tank includes an outer plate whose end is narrowed inward, and an inner plate welded to the outer plate, and the attachment includes an outer surface of the end portion of the outer plate and the inner plate. You may make it hold | maintain in the state which overlap | superposed the end part inner surface or the edge part of the said outer side board, and the edge part of the said inner side board faced. By holding the fuel tank in such a state, the positions of the inner plate and the outer plate are set accurately. Further, by performing welding in such a state, the fuel tank can be formed without a flange portion.
[0012]
When the welding point approaches a distance of 20 [mm] or less from the reference point on the weld line closest to the contact point between the attachment and the fuel tank, the fuel is opened by the opening / closing mechanism. The attachment may be separated from the tank.
[0013]
A welding system according to the present invention is a welding system for welding a fuel tank of a motorcycle having an outer plate whose end is narrowed inward and an inner plate welded to the outer plate. Two or more attachments, a plurality of opening and closing mechanisms for contacting and separating the attachments from a fuel tank of a motorcycle, an automatically operable welding machine for welding, and the opening and closing mechanisms and the welding machine A controller, wherein the controller causes the attachment to contact the fuel tank by the opening / closing mechanism and holds the fuel tank, and then a position of a welding point where welding is performed by the welder. The position of the attachment, and when the relative position of the welding point with respect to the attachment satisfies a predetermined standard, the switch Operating the at least one, characterized in that to separate the attachment from the fuel tank.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a welding method and a welding system according to the present invention will be described with reference to FIGS.
[0015]
As shown in FIG. 1, a welding system 10 according to the present embodiment is a system for welding a fuel tank 12 for a motorcycle, and includes a welding jig 10a (see FIG. 2) that holds the fuel tank 12. , A jig robot 10b for setting the fuel tank 12 held by the welding jig 10a to a predetermined position, a welding robot (welding machine) 10c for performing a welding process, and a controller 10d. The controller 10d is connected to the cylinder 28 of the welding jig 10a (see FIG. 2), the positioning mechanism 44 (see FIG. 7), the jig robot 10b, and the welding robot 10c, and performs overall control of the welding system 10. .
[0016]
As shown in FIG. 2, the welding jig 10 a is a fixing jig for welding the outer plate 14 and the inner plate 16 of the fuel tank 12 of the motorcycle, and an outer jig 18 that supports the outer plate 14. And an inner jig 20 that supports the inner plate 16. In the fuel tank 12, the right side in FIG. 2 is the front (the handle side), and the left side is the rear (the seat side). The fuel tank 12 is placed in an upside down state.
[0017]
As shown in FIG. 1, the outer plate 14 of the fuel tank 12 is supported at its lower part by a plurality of lower support members 22, and at its substantially side and substantially end parts by a plurality of attachments 24. Each attachment 24 is attached to one clamp arm 26 every two or three. A total of eight clamp arms 26 are provided for the left and right objects, and the clamp arms 26 can be individually opened and closed by the cylinders 28.
[0018]
As shown in FIG. 3, the end 15 of the outer plate 14 narrows inward, and the inner surface of the inner plate 16 overlaps the outer surface of the outer plate 14. In this state, the welding robot 10c welds the contact portion 120 (see FIG. 11), which is the overlapping end portion of the outer plate 14 and the inner plate 16, and performs so-called fillet joint one-side welding. A fuel filler port 36 is provided at the lower portion of the outer plate 14.
[0019]
As shown in FIG. 4, the outer jig 18 includes two vertical frames 38 extending from the lower surface of the outer plate 14 toward the rear from a substantially lower side of the fuel filler port 36 at a substantially constant interval, and the vertical frame 38. And four auxiliary frames 40 each extending leftward and rightward, obliquely forward and obliquely rearward. A plurality of lower support members 22 for supporting the outer plate 14 from below are provided on the upper surface of the auxiliary frame 40. A rear end support member 42 that supports the rear end side of the outer plate 14 is provided at the rear end portion of the vertical frame 38. For the lower support member 22 and the rear end support member 42, for example, a resin material such as nylon may be used.
[0020]
At the front end portions of the two vertical frames 38, a positioning mechanism 44 that is inserted into the fuel filler port 36 and holds the fuel tank 12 from the inside is provided.
[0021]
As shown in FIG. 5, a base plate 46 and a cylinder 28 for opening and closing the clamp arm 26 are provided at the respective distal end portions of the auxiliary frame 40, and the base plate 46 and the cylinder 28 are provided with an opening / closing mechanism 47. Is configured. The cylinder 28 can swing with a part of the cylinder tube 28 a being pivotally supported by the base plate 46. The cylinder 28 opens and closes the clamp arm 26 by expanding and contracting the rod 28b.
[0022]
The lower part of the clamp arm 26 is pivotally supported by a shaft 46a above the base plate 46 and can swing. A projecting portion 26 a that slightly protrudes outward is provided at the lower portion of the clamp arm 26, and this projecting portion 26 a is pivotally supported at the tip of the rod 28 b of the cylinder 28. A stopper 26 b that slightly protrudes inward is provided at the lower part of the clamp arm 26. The stopper 26b comes into contact with the upper surface of the base plate 46 when the clamp arm 26 is closed, so that the position of the clamp arm 26 is determined.
[0023]
When the clamp arm 26 is closed by the opening / closing mechanism 47, the first arm portion 26c extending upward from the shaft 46a and the tip of the first arm portion 26c are provided, and the clamp arm 26 is inclined slightly inward. A second arm portion 26d, and a third arm portion 26e that is provided at the tip of the second arm portion 26d and is inclined further inward than the second arm portion 26d. When the clamp arm 26 is closed by such a configuration, the distance between the clamp arm and the outer plate 14 is substantially constant. Note that the installation of the third arm portion 26e is omitted depending on the setting location.
[0024]
The first arm portion 26c, the second arm portion 26d, and the third arm portion 26e are provided with holes 48 to which the attachments 24 can be attached, and two or three attachments 24 are attached to each clamp arm 26. ing.
[0025]
As shown in FIG. 6, the attachment 24 is provided at the tip of the cylinder 50 attached to the hole 48 of the clamp arm 26, the attachment shaft 54 movable along the center hole 52 of the cylinder 50, and the attachment shaft 54. Between the spring receiving plate 56, the adjustment nut 60 screwed into the screw groove 58 provided on the outer peripheral surface of the tip of the cylindrical body 50, the washer 62 adapted to the adjustment nut 60, and the spring receiving plate and the washer 62. And a spring (elastic body) 64 provided on the surface.
[0026]
A spherical ball 66 and a contact portion 68 that can be tilted in any direction while sliding with respect to the ball 66 are provided at the tip of the spring receiving plate 56. The contact portion 68 is composed of two parts 68a and 68b and sandwiches the ball 66.
[0027]
A fixing nut 72 is screwed into a thread groove 70 provided on the outer peripheral surface of the rear end of the cylinder 50, and is fixed with the clamp arm 26 sandwiched between the annular protrusion 74 and the fixing nut 72 at the substantially central portion of the cylinder 50. . Between the annular protrusion 74 and the clamp arm 26, one or more annular shims 76 for adjusting the protrusion length of the attachment 24 with respect to the clamp arm 26 are inserted as necessary.
[0028]
A cylindrical bush 78 having a lubricating function is inserted into the inner surface of the cylindrical body 50. The attachment shaft 54 slides with respect to the bush 78 and can move smoothly.
[0029]
A thread portion 80 having a slightly small diameter is provided at the rear portion of the attachment shaft 54, and a knob 82 and an end stopper 84 are screwed into the screw portion 80. By rotating the knob 82 and the end stopper 84, the compression amount of the spring 64 and the overhang amount of the attachment shaft 54 can be adjusted. After this adjustment, the knob 82 and the end stopper 84 are tightened to each other by a double nut function. Fixed.
[0030]
Further, the amount of compression of the spring 64 can be adjusted by turning the adjusting nut 60. That is, the compression amount of the spring 64 can be adjusted by the knob 82, the end stopper 84, and the adjustment nut 60. In practice, coarse adjustment is preferably performed by the knob 82 and the end stopper 84, and fine adjustment is preferably performed by the adjustment nut 60.
[0031]
Furthermore, when the front end of the contact portion 68 is pushed by the outer plate 14, the attachment shaft 54 moves toward the rear end side. At this time, the attachment shaft 54 compresses the spring 64 and moves a distance corresponding to the elastic force.
[0032]
As shown in FIG. 7, the positioning mechanism 44 is provided in the lower part of the fuel filler opening 36 in the middle part of the two vertical frames 38. The upper part of the positioning mechanism 44 is inserted into the fuel filler port 36. The positioning mechanism 44 includes an insertion member 88 fixed to the frame body 86, a moving member 92 that moves up and down by a rod 90, and is pivotally supported by the moving member 92. When the moving member 92 is lowered, the positioning mechanism 44 is inclined slightly outward. And two hooks 94. The lateral width D of the insertion member 88 is set to be slightly smaller than the inner diameter of the fuel filler port 36.
[0033]
The two hooks 94 are plates extending upward and are set symmetrically. The hook 94 has a protruding portion 94a whose upper portion protrudes slightly outward, a long hole 94b that is long in the longitudinal direction, and a lower swinging hole 94c. The lower part of the long hole 94b is slightly bent outward.
[0034]
Two symmetrical support shafts 88 a protrude from the substantially central height of the insertion member 88. Two symmetrical movement support shafts 92 a protrude from the upper portion of the moving member 92. The fixed support shaft 88a and the moving support shaft 92a protrude toward the front side in the drawing of FIG. 7. The fixed support shaft 88a is inserted into the long hole 94b of the hook 94, and the moving support shaft 92a is the swing hole 94c of the hook 94. Is fitted.
[0035]
When the outer plate 14 is placed on the outer jig 18, the rod 90 is moved upward by a cylinder (not shown). At this time, the two hooks 94 are inclined inward and fit within the lateral width D of the insertion member 88. When the outer plate 14 is placed on the outer jig 18, the upper portion of the insertion member 88 and the upper portion of the hook 94 are inserted into the fuel filler port 36.
[0036]
As shown in FIG. 8, when the rod 90 is lowered, the moving member 92 and the hook 94 are also lowered. The hook 94 is guided by a fixed support shaft 88a inserted into the long hole 94b, and is inclined outward. The protrusion 94 a of the hook 94 projects beyond the inner diameter of the oil filler port 36 and further descends to contact the end of the oil filler port 36 to hold the outer plate 14.
[0037]
As shown in FIG. 9, the inner jig 20 includes a long upper plate 100, an extension rod 102 protruding from the rear end portion of the upper plate 100, a handle 104 provided on the upper surface of the upper plate 100, A plurality of nylon pressing plates 106 that are fixed to the lower surface of the upper plate 100 and conform to the shape of the inner plate 16 are provided. A connecting lever 108 is provided on the rear end portion of the extension rod 102 and the foremost pressing plate 106a. Each pressing plate 106 has a bilaterally symmetric shape projecting about the upper plate, and the left and right end surfaces or the lower surface are matched with the shape of the inner plate 16. The connecting lever 108 is engaged with a connecting hook 110 (see FIG. 2) provided before and after the outer jig 18.
[0038]
As shown in FIG. 10, the controller 10d moves the welding robot controller 130 for controlling the welding robot 10c, the jig robot controller 132 for controlling the jig robot 10b, and the rod 90 of the positioning mechanism 44. The positioning controller 134 and first to eighth cylinder controllers 136, 138, 140, 142, 144, 146, 148, 150 that control the eight cylinders 28, respectively. The welding robot control unit 130 and the jig robot control unit 132 operate the welding robot 10c and the jig robot 10b via a motor driver (not shown). Further, the welding robot control unit 130 and the jig robot control unit 132 can detect the attitude of the welding robot 10c and the jig robot 10b, the positions and speeds of the respective parts, based on feedback signals. Pneumatic valves (not shown) are provided between the positioning control unit 134 and the positioning mechanism 44 and between the first to eighth cylinder control units 136 to 150 and the cylinders 28. 90 and cylinder 28 operate.
[0039]
The controller 10d has a welding control unit 152 as a main control unit, and the welding control unit 152 includes a welding point determination unit that exchanges data with the welding robot control unit 130 and the jig robot control unit 132. 154 is provided. The welding point determination unit 154 gives a control command to the first to eighth cylinder control units 136 to 150.
[0040]
Next, a method of welding the outer plate 14 and the inner plate 16 of the motorcycle fuel tank 12 using the welding system 10 configured as described above will be described with reference to FIGS. The following procedure is basically performed by the controller 10d, and a part of setting work is performed by an operator.
[0041]
First, in step S1 of FIG. 11, the clamp arm 26 of the outer jig 18 is opened (see FIG. 5), and the rod 90 (see FIG. 7) and the hook 94 are raised. In this state, the worker places the outer plate 14 of the fuel tank 12 on the lower support member 22 with the fuel filler port 36 facing downward. At this time, the outer plate 14 is placed by inserting the insertion member 88 of the positioning mechanism 44 into the fuel filler port 36. Since the hook 94 is set to a width narrower than the inner diameter of the oil filler port 36 by being displaced upward, the hook 94 and the oil filler port 36 do not interfere with each other. Further, since the lateral width D of the insertion member 88 is set to be slightly narrower than the inner diameter of the oil filler port 36, the position of the outer plate 14 relative to the outer jig 18 can be simplified by inserting the upper portion of the insert member 88 into the oil filler port 36. And can be set accurately.
[0042]
Next, in step S2, the moving member 92 and the two hooks 94 are lowered by lowering the rod 90 of the positioning mechanism 44. As the two hooks 94 are lowered, the two hooks 94 are inclined outward, and the projecting portion 94a and the end portion of the fuel filler port 36 come into contact with each other. As a result, the outer plate 14 is firmly fixed to the outer jig 18.
[0043]
Next, in step S <b> 3, the inner plate 16 of the fuel tank 12 is placed on the upper portion of the outer plate 14. At this time, the end portion 15 narrowed inward of the outer plate 14 and the end portion of the inner plate 16 are placed so as to substantially overlap. Thereafter, the inner jig 20 is placed on the inner plate 16.
[0044]
Next, in step S <b> 4, each of the eight cylinders 28 is energized to close the clamp arm 26 and bring the stopper 26 b into contact with the upper surface of the base plate 46. The position of the clamp arm 26 is determined by the stopper 26b. When the clamp arm 26 is closed, the contact portion 68 that is the tip portion of each attachment 24 contacts the outer plate 14. At this time, the abutting portion 68 abuts against the outer plate 14 while appropriately compressing the spring 64, so that the outer plate 14 is pressed according to the compression amount of the spring 64. This pressing force can be adjusted by the rotation of the adjusting nut 60 or the knob 82, and it is preferable that an operator adjusts the pressing force in advance so as to obtain an appropriate pressing force.
[0045]
Since the position of the outer plate 14 is set by the abutment portion 68 of the attachment 24 holding the outer plate 14, for example, it is possible to correct bending due to the weight of the outer plate 14. In addition, since the eight clamp arms 26 are arranged symmetrically four by four, the fuel tank 12 can be held in a well-balanced manner.
[0046]
Further, since the abutting portion 68 has a structure that can tilt with respect to the ball 66, the abutting portion 68 abuts on the outer surface without any contact with the outer surface.
[0047]
Next, in step S <b> 5, the worker engages the connection levers 108 provided at both ends of the inner jig 20 with the connection hook 110. Since the holding plate 106 of the inner jig 20 fits the inner plate 16, the inner plate 16 is accurately positioned and fixed with respect to the outer plate 14.
[0048]
Next, in step S6, welding of the outer plate 14 and the inner plate 16 is started by the welding robot 10c (see FIG. 1). The welding method is a welding method in which continuous welding is performed along a welding line (see FIG. 14) V, and includes TIG (inert-gas tungsten-arc welding) welding, MIG (inert-gas metal-arc welding). Various welding methods such as welding can be employed.
[0049]
As shown by points Q <b> 1 to Q <b> 12 representing the welding order in FIG. 12, welding is performed twice on the fuel tank 12. Points Q1 to Q12 are points on the weld line V, of which point Q1 is a start point, point Q6 is a temporary stop point, point Q7 is a restart point, and point Q12 is an end point. . Further, the points Q2 to Q6 and the points Q8 to Q11 are welds closest to the contact point P (see FIGS. 13 and 14) between the attachment 24 and the fuel tank 12 of the clamp arm 26 arranged in the vicinity thereof. Reference point on line V.
[0050]
On the center line of the fuel tank 12, welding is started from the foremost point Q1, and welding is sequentially performed to points Q2 to Q6. The point Q6 is on the center line of the fuel tank 12 and is the rearmost point. After welding to point Q6, the welding is interrupted once and moved to point Q7. Point Q7 is a point in the vicinity of point Q1, and is set at a location where a lap weld is formed. Welding is started again from point Q7, and welding is sequentially performed to points Q7 to Q12. Point Q12 is a point in the vicinity of point Q7, and is set at a location where a lap weld is formed. The welding of such a path is performed by the operation of the welding robot 10c (see FIG. 1), but the welding may be performed while 10b (see FIG. 1) cooperates.
[0051]
Next, a detailed method for performing welding in the order shown in FIG. 12 will be described.
[0052]
That is, welding is performed along the welding line V in step S7 of FIG. For example, when welding is performed from the point Q1 to the point Q2, as shown in FIGS. 13 and 14, the electrode 122 (or arc or the like) is provided along the contact portion 120 between the end portion of the inner plate 16 and the outer plate 14. Move to move the welding. A weld bead 124 is formed on the contact portion 120 so that the inner plate 16 and the outer plate 14 are welded.
[0053]
By the way, since the welding part M at the time of welding melts at a high temperature, deformation due to melting occurs. In particular, when the workpiece is constrained, when the melted portion is cooled and solidified, a weld bead 124 having distortion (thermal strain) inside is formed without being allowed to be deformed. The weld bead 124 having such a thermal strain may generate a crack.
[0054]
In welding using the welding jig 10a, when the weld bead 124 is formed by heat and the welded portion expands, the outer plate 14 is deformed so as to be pushed outward as indicated by an arrow A0. To do. At this time, the contact point P in contact with the contact portion 68 of the attachment 24 receives a force A1 in accordance with the arrow A0. This force A1 is determined by the direction and size of the arrow A0 and the position of the contact point P, and is a force that is directed outward. The contact P compresses the spring 64 via the contact portion 68 by the force A1. When the force A1 is small, the compression amount of the spring 64 is small, and when the force A1 is large, the compression amount of the spring 64 is large.
[0055]
In this way, the initial contact point P can be displaced to a position Px where the elastic force generated by the compression of the spring 64 and the force A1 are balanced. Therefore, due to the action of the attachment 24, the weld bead 124 condenses while absorbing the thermal strain at a high temperature after welding, and the thermal strain contained in the weld bead 124 after cooling becomes very small.
[0056]
Further, since the distance between the contact point P and the position Px is very small, this distance does not cause a problem as a dimensional error.
[0057]
In FIG. 13, the arrow A <b> 0 indicating the direction of expansion due to the formation of the weld bead 124 is illustrated as the direction substantially coincident with the direction of the end face of the outer plate 14, but the direction of the arrow A <b> 0 is any direction Thermal strain can be absorbed. That is, when the arrow A0 is directed outward, the spring 64 of the attachment 24 is compressed according to the direction and size of the arrow A0 to absorb thermal strain.
[0058]
Further, when the arrow A0 is directed inward, the weld bead 124 is formed while contracting, and the attachment 24 does not restrain the contraction deformation.
[0059]
Furthermore, in this step S7, the welding point determination unit 154 performs welding based on data supplied from the welding robot control unit 130 and the jig robot control unit 132 (see FIG. 14). Determine the position.
[0060]
Next, in step S8, the welding point determination unit 154 calculates a distance L0 between the position of the welding point M and a reference point (for example, the point Q2), and compares the distance L0 with a preset distance L1. Do. When the distance L0 is smaller than the distance L1, the process returns to step S7 and welding is continued. When the distance L0 is larger than the distance L1, for example, when the welding point M in FIG. 12 exceeds the point B of the distance L0 from the point Q2, the process proceeds to step S9.
[0061]
In step S <b> 9, the welding point determination unit 154 issues a command to the cylinder 28 of the corresponding opening / closing mechanism 47 to open the clamp arm 26 and separate the attachment 24 from the fuel tank 12. For example, as shown in FIG. 12, when welding is performed toward the point Q2, a command is given to the first cylinder control unit 136 that controls the cylinder 28 corresponding to the point Q2, and only the attachment 24 corresponding to the point Q2 is provided. open.
[0062]
When the outer plate 14 is held by the attachment 24, the thermal strain can be absorbed by the spring 64, but there is some restraining force due to the elastic force of the spring 64, and a weak thermal strain corresponding to the restraining force is present. May occur. In step S9, the attachment force 24 is separated from the outer plate 14 so that the binding force is eliminated, and the occurrence of thermal distortion can be further suppressed.
[0063]
In addition, since the original effect | action of hold | maintaining the outer side board 14 will be lose | eliminated if the timing which leaves | separates the attachment 24 is too early, it is necessary to set the distance L0 to an appropriate value. In practice, the distance L0 is preferably 20 [mm] or less. When the distance L0 is set to 20 [mm] and the welding point M reaches the point 20 [mm], which is the distance L0 from the point Q2, and the attachment 24 is separated, the location about 25 [mm] from the point Q2 is Welding is already complete and almost solidified. Therefore, even if the attachment 24 is separated, the position of the outer plate 14 is not shifted. Further, since the attachment 24 is separated only at a place where the welding is almost completed, the right and left balance in holding the fuel tank 12 is not lost.
[0064]
Next, in step S10, it is determined whether or not the welding point M has reached the point Q6. When the welding point M reaches the point Q6, the welding is interrupted once and moved to the point Q7 (step S11), and then the process returns to step S6.
[0065]
Next, in step S12, it is determined whether or not the welding point M has reached the point Q12. When the welding point M does not reach the point Q12, the process returns to step S7. When the welding point M reaches the point Q12, the process proceeds to step S13.
[0066]
In step S13, welding is terminated. After finishing the welding, the rod 90 of the positioning mechanism 44 is raised. Thereafter, the worker releases the connecting lever 108, removes the inner jig 20, and removes the fuel tank 12 after welding (step S14).
[0067]
In steps S7 and S8, an example is shown in which the positional relationship between the welding point M and the reference point (for example, the point Q2) is determined by real-time processing. The posture may be associated in advance, and the attachment 24 may be separated when the welding robot 10c assumes a predetermined posture. Further, the attachment 24 may be sequentially operated after a predetermined time by a time counting process from the start of welding.
[0068]
As described above, according to the welding system 10 and the welding method according to the present embodiment, when the welding point M moves along the welding line V, the attachment 24 is attached from the fuel tank 12 in the order in which the welding point M approaches. Therefore, the restraining force of the outer plate 14 of the fuel tank 12 is eliminated, the influence of thermal distortion due to welding can be reduced, and the occurrence of cracks can be suppressed. As a result, the yield of the fuel tank 12 can be improved.
[0069]
Further, since the attachment 24 holds the fuel tank 12 via the spring 64, the influence of thermal distortion due to welding can be reduced even while the attachment 24 is holding the fuel tank 12.
[0070]
Further, since the attachment 24 is welded by holding the outer surface of the end portion 15 of the outer plate 14 and the inner surface of the end portion of the inner plate 16 in an overlapped state, the flange 24 is attached to the fuel tank 12 after welding. There is no. Therefore, it is suitable as a fuel tank for a motorcycle that requires an aesthetic appearance such as an American type.
[0071]
Although the above-described welding jig 10 a has been described as an example having eight clamp arms 26, the number of clamp arms 26 may be appropriately increased or decreased depending on the size and shape of the fuel tank 12. For example, a total of four clamp arms 26 of two each on the left and right may be provided and arranged symmetrically. Further, the attachment 24 attached to one clamp arm 26 may be appropriately increased or decreased depending on the size and shape of the fuel tank 12.
[0072]
Of course, the welding method and the welding system according to the present invention are not limited to the above-described embodiments, and various configurations or steps can be adopted without departing from the gist of the present invention.
[0073]
【The invention's effect】
As described above, according to the welding method and the welding system according to the present invention, when welding a fuel tank of a motorcycle, the effect of reducing the influence of thermal distortion due to welding and suppressing the occurrence of cracks is achieved. can do.
[Brief description of the drawings]
FIG. 1 is a schematic view of a welding system according to the present embodiment.
FIG. 2 is a perspective view of a welding jig and a fuel tank of a motorcycle.
FIG. 3 is a front sectional view of a welding jig and a fuel tank of a motorcycle.
Fig. 4 is a partially omitted side view of a welding jig and a fuel tank of a motorcycle.
FIG. 5 is a front view showing a cylinder, a clamp arm, an attachment, and a peripheral portion thereof.
FIG. 6 is a cross-sectional view of the attachment.
FIG. 7 is a front view of the positioning mechanism with the hook raised.
FIG. 8 is a front view of the positioning mechanism with the hook lowered.
FIG. 9 is a perspective view of an inner jig, an inner plate, and an outer plate.
FIG. 10 is a block diagram illustrating a configuration of a controller.
FIG. 11 is a flowchart showing a method of performing welding using the welding system according to the present embodiment.
FIG. 12 is a schematic diagram showing a welding path.
FIG. 13 is a schematic view showing a state in which welding is performed while pressing an outer plate with an attachment.
FIG. 14 is a schematic diagram showing a welding line, a contact point, a reference point, and a welding point.
FIG. 15 is a perspective view of a fuel tank having a flange portion.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Welding system 10a ... Welding jig 10b ... Jig robot 10c ... Welding robot 10d ... Controller 12 ... Fuel tank 14 ... Outer plate 16 ... Inner plate 15 ... End part 18 ... Outer jig 20 ... Inner jig 22 ... Lower support member 24 ... Attachment 26 ... Clamp arm 28 ... Cylinder 36 ... Filling port 44 ... Positioning mechanism 50 ... Cylindrical body 56 ... Spring receiving plate 58 ... Screw groove 60 ... Adjusting nut 62 ... Washer 64 ... Spring 66 ... Ball 68 ... Contact part 82 ... Knob 84 ... End stopper 88 ... Insert member 90 ... Rod 94 ... Hook 94a ... Projection part 94b ... Long hole 94c ... Swing hole 106, 106a ... Pressing plate 108 ... Connection lever 110 ... Connection hook 120 ... Contact part 124 ... weld bead B, Q1-Q12 ... point V ... welding line M ... welding point P ... contact point L0, 1 ... distance

Claims (5)

A welding method comprising one or a plurality of attachments, and welding the fuel tank using a plurality of opening / closing mechanisms for bringing the attachment into contact with and separating from the fuel tank of a motorcycle,
Holding the fuel tank by bringing the attachment into contact with the fuel tank by the opening and closing mechanism;
Separating the attachment from the fuel tank by the opening / closing mechanism in the order in which the welding points approach when the welding point to be welded moves along the weld line;
A welding method characterized by comprising: The welding method according to claim 1,
The welding method, wherein the attachment holds the fuel tank via an elastic body. The welding method according to claim 1 or 2,
The fuel tank has an outer plate whose end is narrowed inward,
An inner plate welded to the outer plate;
Have
The attachment holds the outer surface of the outer plate and the inner surface of the inner plate, or holds the end of the outer plate and the end of the inner plate in contact with each other. Welding method. In the welding method of any one of Claims 1-3,
When the welding point approaches a distance of 20 [mm] or less from the reference point on the weld line closest to the contact point between the attachment and the fuel tank, the fuel is opened by the opening / closing mechanism. A welding method characterized in that the attachment is separated from the tank. An outer plate with the end narrowed inward,
An inner plate welded to the outer plate;
A welding system for welding a fuel tank of a motorcycle having
A plurality of opening / closing mechanisms comprising one or a plurality of attachments, wherein the attachments abut against and separate from the fuel tank of the motorcycle;
An automatically operable welder for welding,
A controller connected to the opening / closing mechanism and the welding machine;
Have
The controller holds the fuel tank by bringing the attachment into contact with the fuel tank by the opening and closing mechanism,
A position of a welding point where welding is performed by the welder and a position of the attachment are determined, and when a relative position of the welding point with respect to the attachment satisfies a predetermined reference, at least one of the opening / closing mechanisms The welding system is operated to move the attachment away from the fuel tank.

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