CN1161264A - seam welder - Google Patents

Abstract

A seam welder capable of preventing a drop in current density on conventional circular seam welders and capable of performing circular seam welding without welding defects. It is composed of: a pair of upper and lower electrodes 10 and 20 with circular opposing surfaces; the two electrodes 10 and 20 are arranged obliquely with respect to the main axis C perpendicular to the workpiece W; the two electrodes 10 and 20 are respectively positioned at At one point 10a and 20a of the periphery of the above-mentioned opposite surface, the object to be welded is in contact with; between the joints 10a and 20a, the object to be welded W is clamped and moved around the above-mentioned main axis C, along the The movement loci of the joints 10a and 20a are welded.

Description

seam welder

The present invention relates to a seam welding machine which is suitable for welding containers having airtightness requirements such as fuel tanks of automobiles.

Generally, the structure of the seam welding machine is that, as shown in Fig. 4, the object W to be welded is clamped between a pair of disk-shaped electrodes D and D; Object W, so welding is carried out along the trajectory of the contact between the two electrodes D, D. In this way, welding of a highly airtight continuous seam can be performed. Therefore, in the past, for welding the body T of the automobile fuel tank as shown in Figure 5 (referring to the welding of the fuel tank body T periphery E position shown in the figure), this seam welder is just often used. However, when an oil filling port P having the same airtightness requirements as in the oil tank is welded on the tank body T, the flange portion PF located at the end of the pipe as the oil filling port P is required to be Welding is performed on relatively small circumferences of the order of several tens of millimeters. However, when welding along such a small circumference, the above-mentioned conventional seam welding machine has not been actually used for welding in this case due to the extreme difficulty in its structure. Therefore, as a conventional example, a circular seam welder used for welding along such a small-diameter circumference is disclosed in Japanese Patent Application Laid-Open No. 61-180680.

The structure of this conventional seam welding machine is that, as shown in FIG. 6, the cylindrical rotating electrode R as the upper electrode is kept in an inclined state with respect to the workpiece W placed on the lower electrode L; While a point on the lower edge of the cylindrical rotating electrode R is in contact with the object to be welded W, the upper part of the cylindrical rotating electrode R is placed between the central axis C1 of the cylindrical rotating electrode R and the object to be welded. W rotates around the fixed normal line C2 at the intersection of the two; thus, the edge RE of the cylindrical rotating electrode R rotates on the object W to be welded for welding. In this way, seam welding can be performed along the circumference of a small diameter.

However, in such a conventional seam welder, since the lower electrode L is in surface contact with the workpiece W due to its structure, the welding current is diffused by the planar flat lower electrode L, thereby reducing the current density. , prone to problems such as poor welding. The present invention has been made in view of this problem, and an object of the present invention is to provide a seam welder capable of reliably performing circular seam welding.

The feature of the seam welding machine of the present invention is that it has: an upper and lower pair of upper and lower main shafts (30) and lower main shafts (40), which rotate at the same speed and in the same direction, and are arranged on the same shaft, are fixed The upper support member (31) on the lower end of the upper main shaft (30), the lower support member (41) fixed on the upper end of the lower main shaft (40), is installed on the upper support member (31), its lower end surface has The upper electrode (10) of the circular profile, and the lower electrode (20) that is installed on the lower support member (41) and has a circular profile on its upper end surface; the center of the circular profile of the above-mentioned upper electrode (10) The shaft (C10) and the central axis (C20) of the circular profile of the lower electrode (20) are only at the same angle Q with respect to the main axis (C) of the upper and lower pair of main shafts (30, 40) and point to the same direction. The direction is tilted.

According to this seam welder, both upper and lower electrodes (10, 20) are set in an inclined state with respect to the main axis (C). Therefore, each of the two electrodes (10, 20) is in contact with the object to be welded at one point in the periphery of the opposite surface. There is no surface contact like the conventional lower electrode. In this way, a welding current with a high current density can be supplied from both the upper and lower electrodes.

The seam welding machine of the present invention can prevent welding defects and reliably perform circular seam welding because it can provide a welding current with a higher current density than conventional ones.

Fig. 1 is a drawing showing main parts of the seam welding machine in this embodiment. A part near the upper and lower electrodes is a cross-sectional side view.

Figure 2. Front view of the seam welder in this example.

Figure 3, a side view of the seam welder in this example.

Fig. 4 is a schematic diagram of a conventional general seam welder.

Figure 5, a longitudinal section view of the fuel tank.

Fig. 6 is a schematic diagram of a conventional circular seam welder. Quoted from Fig. 1 in the patent publication "Japanese Patent Laid-Open No. 61-180680".

Next, referring to FIG. 1 to FIG. 3 , an embodiment of the present invention will be described. 2 and 3 are overall views of the seam welder S in this example. The symbol 1 in the figure is the frame of the welding machine S. At a position slightly downward from the center of the frame 1, a workbench 2 is provided, and the workbench 2 fixes the object W to be welded in a substantially horizontal state. . A pair of electrodes 10 and 20 are arranged at upper and lower positions relative to the workpiece W to be welded.

The upper and lower electrodes 10 and 20, as clearly shown in FIGS. 1 and 3, are generally cup-shaped. On the opposite side of the two electrodes, that is, the lower side of the upper electrode 10 and the upper side of the lower electrode 20 are cylindrical structures with the same diameter. In this cylinder, the protrusion WP of the object W to be welded is accommodated. The electrodes 10 and 20 may also be disk-shaped if there is no protrusion on the object W to be welded. The electrodes 10 and 20, on opposite end faces, need to be circular in shape. The two electrodes 10 and 20 are arranged in such a way that their respective central axes C10 and C20 are only inclined in the same direction at the same angle θ with respect to the main axis C perpendicular to the workpiece W to be welded. The so-called tilting in the same direction here means that both the central axes C10 and C20 are in one plane including the main axis C.

The upper and lower electrodes 10 and 20 are arranged symmetrically up and down by approximately the same mechanism. First, the supporting structure of the upper electrode 10 will be described. As shown in FIG. 1 , an upper supporting member 31 is attached to a lower end portion of an upper spindle 30 placed in a direction perpendicular to the workpiece W to be welded. A tilt shaft 32 is rotatably attached to the upper supporting member 31 so as to be tilted at an angle of θ with respect to the axis of the upper main shaft 30 (main axis C). The upper electrode 10 is fixed to the lower end of the tilt shaft 32 via an insulating sheet 33 and a holding member 34 . The center axis C10 of the upper electrode 10 is the same as the axis of the tilt axis 32 . Therefore, the upper electrode 10 is in contact with the object W to be welded only at an inclination angle θ with respect to the main axis C. As shown in FIG. Therefore, the upper electrode 10 is in contact with the object W to be welded at a point 10 a on the periphery of the lower surface (the surface facing the lower electrode 20 ). The main axis C of the upper main shaft 30 and the central axis C10 of the upper electrode 10 intersect on the surface of the object W to be welded as shown in FIG. 1 .

The lower electrode 20 is supported by a vertically symmetrical structure with respect to the upper electrode 10 as described above. That is to say, it is on the same axis as the above-mentioned upper main shaft 30, that is, the lower main shaft 40 is arranged on the main axis C, and the lower support member 41 is fixed on the upper end of the lower main shaft 40, and the lower support member 41 only tilts the angle θ, and the upper end of the tilt shaft 42 supported rotatably is fixed to the lower electrode 20 through the insulating sheet 43 and the holding member 44 . The lower main shaft 40 and the upper main shaft 30 are rotated synchronously in the same direction at the same speed by a synchronous mechanism described later. In addition, the lower inclined axis 42 is inclined in the same direction at the same angle θ as the upper inclined axis 32 . That is, both the lower inclined axis 42 and the upper inclined axis 32 are located in the same plane including the main axis C, and when viewed from the top of FIGS. 1 to 3 , the two inclined axes 32 and 42 are mutually coincide. Therefore, the lower electrode 20 is also in contact with the object W to be welded at a point 20 a on the periphery of the upper surface (the surface facing the upper electrode 10 ). In this way, the object to be welded W is sandwiched between one point 10 a on the periphery of the upper electrode 10 and one point 20 a on the periphery of the lower electrode 20 . Therefore, each of the two electrodes 10 and 20 is in point contact with the object W to be welded, not in surface contact. The main axis C of the lower main shaft 40 and the central axis C20 of the lower electrode 20 intersect on the lower surface of the object W to be welded, as shown in FIG. 2 .

Next, the spindle rotation mechanism, the vertical sliding mechanism of the upper spindle 30, and the synchronization mechanism will be described. As shown in FIG. 2 , a drive motor 50 is disposed on the upper portion of the frame 1 . The rotational output of the driving motor 50 is transmitted to the driven side pulley 52 mounted coaxially with the upper main shaft 30 through the driving side pulley 58 and the transmission belt 51 . The driven side pulley 52 is fixed by a nut 53 . The nut 53 is rotatably supported by the frame 1 via a fixing clip 54 . The upper main shaft 30 is a ball spline shaft, which cannot rotate relative to the nut 53 . On the other hand, the upper spindle 30 can relatively move up and down with respect to the nut 53 . On the top of the frame 1, a cylinder 55 is installed facing downwards. The upper end of the upper main shaft 30 is connected to the piston rod 55 a of the cylinder 55 via joints 56 and 57 . The lower joint 57 is rotatable relative to the piston rod 55 a on the upper spindle 30 . According to the above configuration, the upper spindle 30 rotates around the main axis C by the action of the rotation mechanism mainly composed of the motor 50 . In addition, independently of the above rotation, the upper spindle 30 can move up and down within a certain stroke along the direction of the main axis C through the vertical sliding mechanism mainly composed of the cylinder 55 .

On the upper main shaft 30 , in addition to the above-mentioned upper supporting member 31 , a gear set is arranged. This gear set is made up of four spur gears 70,71,72,73 and two bevel gears 74,75. The spur gear 70 is fixed on the upper main shaft 30, and the two rotate as a whole. The spur gears 71 and 72 are mounted on the slider 60 in combination. The slider 60 is rotatable on the upper spindle 30 via the bearings 60a, 60a. Furthermore, it is supported by the frame 1 so as to be movable up and down by the linear slide mechanism 61 . Therefore, the slider 60 is integrated with the upper shaft 30 and slides in the vertical direction. However, due to the restriction of the frame 1, the slide block 60 cannot rotate, so only the upper main shaft 30 is allowed to rotate independently. The spur gear 71 is fixed to the upper end of the shaft 62 while meshing with the spur gear 70 , and the rotatable shaft 62 is supported by the slider 60 . A spur gear 72 is fixed to the lower end of the shaft 62 . This spur gear 72 rotates integrally with the above-mentioned spur gear 71 .

The spur gear 72 is meshed with the spur gear 73 . The spur gear 73 is mounted on the upper main shaft 30 through a bearing device not shown in the figure, and can rotate independently of the upper main shaft 30 . On the lower side of the spur gear 73, a bevel gear 74 is disposed, and rotates integrally with the spur gear 73. A bevel gear 75 meshed with the bevel gear 74 is fixed to the upper end of the tilt shaft 32 . With the gear set thus constituted, the inclined shaft 32 is rotated at the given rotation speed through the transmission order of the upper main shaft 30→spur gear 70→71→72→73→bevel gear 74→75.

Here, the gear sets 70 to 75 should have such a tooth number relationship, that is, the self-rotation can offset the revolution, so that the upper electrode 10 does not rotate. That is, assuming that the tilt shaft 32 is fixed by the upper supporting member 31 , when the upper main shaft 30 rotates one revolution in the clockwise direction, the upper electrode 10 makes one revolution around the upper main shaft 30 . However, when the upper main shaft 30 rotates clockwise for one revolution, the gear sets 70 to 75 make the upper electrode 10 rotate counterclockwise for one revolution. Therefore, the revolution around the main axis C of the upper electrode 10 due to the rotation of the upper main shaft 30 is offset by the rotation of the upper electrode 10 due to the action of the gear sets 70 to 75, and the result is , the upper electrode 10 does not rotate. Even if the upper spindle 30 rotates, the upper electrode 10 does not rotate, but the direction of the central axis C10 rotates around the upper spindle 30 . Therefore, the upper electrode 10 will not slide relative to the object W to be welded, and the contact between the upper electrode 10 and the object to be welded rotates 360° on the circular hub of the lower end surface of the upper electrode 10 .

Next, a synchronization mechanism for synchronizing the upper electrode 10 and the lower electrode 20 will be described. A long synchronous shaft 80 is coaxially connected to the output shaft of the motor 50 facing downward. The lower end of the synchronous shaft 80 is rotatably supported by the frame 1 via a universal joint 81 . Near the lower end of the synchronous shaft 80, a pulley 82 is fixed. The rotation of this pulley 82 is transmitted to a pulley 84 fixed to the lower shaft 40 via a transmission belt 83 . Accordingly, the lower main shaft 40 rotates synchronously with the above-mentioned upper main shaft 30 at the same speed and in the same direction, using the motor 50 as a common driving source. The structure between the lower main shaft 40 and the lower electrode 20 is, as described above, vertically symmetrical with the upper side, and basically the same structure, but there is no structure corresponding to the upper vertical sliding mechanism, so the lower electrode 20 cannot Do move up and down. Therefore, the lower main shaft 40 is not a spline shaft, but is only supported for rotation. In addition, since the lower spindle 40 cannot move up and down, the slider 42 on the lower side is also fixed by the frame 1 so that it cannot move up and down. In addition, the gear set that rotates the tilt shaft 42 has exactly the same structure as the upper gear set.

As shown in FIG. 3, on the upper and lower holding members 34 and 44, electric wires 3 and 4 for supplying welding current to the electrodes 10 and 20 are connected. A welding current is supplied to the two electrodes 10 and 20 via the wires 3 and 4 from a power source 5 . 6 in Fig. 2 is the operation panel of this welding machine S. Through the operation panel 6, various operations such as supplying and shutting off welding current, starting and stopping the motor 50, and the like are performed.

According to the seam welding machine S in this example constituted as above, after the object to be welded W is fixed on the workbench 2-2, the cylinder 55 moves in the direction of its ejection, so that the upper electrode 10 is pressed by the object to be welded W. . Therefore, the object to be welded W is sandwiched between the upper and lower electrodes 10 and 20 . In this state, since the central axes C10 and C20 of the two electrodes 10 and 20 are only inclined at an angle of θ with respect to the main axis C perpendicular to the object W to be welded, the two The electrodes 10 and 20 are not in surface contact, but at points 10a and 20a in the periphery of their end faces with circular contours. Furthermore, since the joints 10a and 20a overlap each other in plan view, as a result, the object to be welded W is sandwiched between the two joints 10a and 20a.

)而移动。这样，缝焊接就沿着两接点10a和20a的移动轨迹而进行。而且，两电极10和20，由于齿轮组70至75的作用，在主轴线C周围的公转被其自转所抵消，所以相对于机架1的方位不会变化。因此，相对于被焊接物W，就不会有圆周方向的滑动。这样，与被焊接物W之间不会出现阻力，两接点10a和20a能顺利地移动。Then, after starting the motor 50, the upper and lower two main shafts 30 and 40 rotate synchronously in the same direction at the same speed. Thus, the two support members 31 and 41 also generate synchronous rotations around the main axis C at the same speed and in the same direction. Therefore, the two electrodes 10 and 20 revolve around the main axis C with their respective central axes C10 and C20 inclined by the angle θ with respect to the main axis C. Therefore, the contact points 10a and 20a of the two electrodes 10 and 20, while clamping the object to be welded W, are along the circumference centered on the main axis C (if the radius of the electrodes 10 and 20 is r, the radius of the contact track for

) to move. Thus, the seam welding is performed along the moving loci of the two joints 10a and 20a. Moreover, due to the effect of the gear sets 70 to 75, the revolution of the two electrodes 10 and 20 around the main axis C is offset by its rotation, so the orientation relative to the frame 1 will not change. Therefore, there is no slip in the circumferential direction with respect to the workpiece W to be welded. In this way, there is no resistance to the object W to be welded, and the two joints 10a and 20a can move smoothly.

Like this, two electrodes 10 and 20, owing to being in contact with welded object W on a point 10a and 20a in the periphery of opposite face respectively, so just can not appear, as in the past, because lower electrode L is relative to welded object W For surface contact, the supplied welding current is dispersed to lower the current density. Therefore, high-quality circular seam welding without welding defects can be performed.

In addition, like the electrodes 10 and 20, since the holding members 34 and 44 also keep their orientation relative to the frame 1 unchanged when they revolve around the main axis C, the electrodes connected to the holding members 34 and 44 The wires 3 and 4 are not wound around the holding members 34 and 44 . Thereby, it is not necessary to adopt a sliding portion power supply method in which current is supplied through the sliding portion of the rotating shaft, which is used in a conventional general seam welding machine (see FIG. 4 ). This eliminates problems such as current loss, electrical corrosion, or heat generation that have been problematic in the past, and improves welding efficiency and equipment maintainability. In particular, since the heat generation of the sliding portion is largely suppressed, conventional cooling devices may be unnecessary, or a simple device may suffice.

Claims (6)

1. seam welder is characterized in that it comprises: a pair of up and down, that rotate to same direction with same speed and be installed in last main shaft (30) and lower main axis (40) on the same axle; Be fixed on the last holding components (31) of the lower end of main shaft (30); Be fixed on the following holding components (41) of the upper end of lower main axis (40); Be installed in that holding components (31) is gone up and its lower surface has circular wheel Guo's top electrode (10); Be installed in down that holding components (41) is gone up and its upper surface has circular wheel Guo's bottom electrode (20); The circular wheel Guo's of above-mentioned top electrode (10) the central shaft (C10) and the circular wheel Guo's of above-mentioned bottom electrode (20) central shaft (C20) is with respect to the main shaft (C) of a pair of up and down main shaft (30 and 40), to the same direction angle θ that only tilts.

2. as the seam welder described in the claim 1, it is characterized by: with respect to last holding components (31), top electrode (10) can be done rotation around above-mentioned central shaft (C10); With respect to following holding components (41), bottom electrode (20) can be done rotation around above-mentioned central shaft (C20).

3. as the seam welder described in the claim 1, it is characterized by: top electrode (10) is connected in main shaft (30) by such gear train, this gear train makes, since the rotation of last main shaft (30) and top electrode (10) go up produce, in above-mentioned main shaft (C) revolution on every side, certainly transfer counteracting by what produce on every side at above-mentioned central shaft (C10); Bottom electrode (20) is connected in lower main axis (40) by such gear train, this gear train makes, since the rotation of lower main axis (40) and bottom electrode (20) go up produce, in above-mentioned main shaft (C) revolution on every side, certainly transfer counteracting by what produce on every side at above-mentioned central shaft (C20).

4. as the seam welder described in the claim 1, it is characterized by: go up main shaft (30) and lower main axis (40), driven by same motor (50).

5. as the seam welder described in the claim 1, it is characterized by: with respect to lower main axis (40), last main shaft (30) can be done axial relatively moving.

6. as the seam welder described in the claim 1, it is characterized by: top electrode (10) and bottom electrode (20) are cylindric.

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