JP2005342782A - Ring mash welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ring mash welding method capable of reliably welding a tubular work with the other work to be welded with high welding strength. <P>SOLUTION: In the ring mash welding method, a tubular second work 9 is held by a welding electrode 7, and a tip of the tubular second work 9 overlaps a void part of a first work 8 supported by a welding electrode 7 at an overlapping margin. The welding current runs in a state in which the pressure is applied between the first work 8 and the tubular second work 9, and the tip of the tubular second work 9 is instantaneously pressed into the void part of the first work 8 to weld an inner circumferential surface of the first work 8 to an outer circumferential surface of the tip of the tubular second work 9. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a ring mash welding method in which welding portions are slightly overlapped, pressed and energized at once, and engaged to perform welding.

Ring mash welding is known as one welding method for welding the first workpiece and the second workpiece. In this ring mash welding method, the outer diameter of the welded portion of the first work piece is made somewhat larger than the diameter of the inner peripheral surface forming the hole of the second work piece, and the first work piece is welded. Align the welded part of the weldment with the hole of the second work piece, press it slightly over and hold it, and pressurize and apply current in the same way as normal welding to soften the welded part. The welding portion of the first workpiece is pushed into a hollow portion such as a hole of the second workpiece to be welded (see Patent Document 1). A welded product welded by such a ring mash welding method exhibits a large weld strength depending on the direction of force because the welded portion of one welded product is pushed into the welded portion of the other welded product.
JP 2004-17048 A

  However, as shown in FIG. 4B, when a thin pipe-shaped workpiece 11 is aligned and overlapped with the empty portion 12a of another workpiece 12 and ring mash welding is performed, as shown in FIG. There is a problem that the softened portion of the thin-walled pipe-shaped workpiece 11 is deformed or distorted. This is because the welded portion of the thin-walled pipe-shaped workpiece 11 is softened and pushed into the hollow portion 12a of the other workpiece 12 by the force indicated by the arrow A in the downward vertical direction in the drawing. This is because it is deformed or distorted in the vicinity of the work piece 12.

Therefore, when a thin pipe-shaped workpiece 11 that is deformed or distorted by ring mash welding is fixed to another workpiece 12, plasma arc welding or brazing is performed. . However, in the case of plasma arc welding, if a skilled worker performs welding, satisfactory welding strength can be obtained. However, even if the skilled worker performs welding, there is a drawback that it takes a considerable amount of time for welding. There is a drawback that the welded portion is discolored.
Further, in the case of brazing, there is a drawback that satisfactory strength cannot be obtained for the time required for the brazing operation.

In the present invention, as in normal resistance welding, a welding method that uses a pair of upper and lower welding electrodes and performs ring mash welding to the other workpiece without deforming or distorting one of the thin pipe-like workpieces. It is an issue to provide.

In order to solve the above-mentioned problem, the first invention is such that at least a part of the inner peripheral surface of the first workpiece to be welded having an inner peripheral surface defining a void is somewhat larger than the void. In the mash welding method of welding the outer peripheral surface of the tip of the pipe-shaped second workpiece having an outer shape, a reinforcing member is attached to the cavity in the tip of the pipe-shaped second workpiece, A pipe-shaped second workpiece is gripped by one welding electrode, and the pipe-shaped second workpiece is inserted into the empty portion of the first workpiece supported by the other welding electrode. The top end portions are overlapped with each other, and a welding current is applied in a state where a pressure is applied between the first workpiece and the pipe-shaped second workpiece, and the first current is instantaneously applied. Push the tip of the pipe-shaped second workpiece into the empty portion of the workpiece, There is provided a ring mash welding method for bonding the outer peripheral surface of the distal end portion of the first year inner peripheral surface and the pipe-shaped second weld object of the object to be welded.
A second invention provides the ring mash welding method according to the first invention, wherein the reinforcing member is a closed plate having a contour adapted to the cavity, a plate having a hole, or a cylindrical body. Is.
According to a third invention, in the first invention or the second invention, the one welding electrode extends to an outer position corresponding to an inner position of the pipe-shaped second workpiece on the reinforcing member. A ring mash welding method is provided.

In order to solve the above-described problem, a fourth invention is a mash welding method for welding a first workpiece to be welded to a tip portion of a pipe-shaped second workpiece having a cavity. A protrusion having a diameter larger than the diameter of the inner peripheral surface forming the cavity at the tip of the second workpiece is formed on the first workpiece, and one welding electrode is formed in the pipe shape. The second workpiece to be welded is held, and the inner peripheral surface of the pipe-shaped second workpiece is overlapped with the protruding portion of the first workpiece to be supported by the other welding electrode. The protruding portion of the first workpiece is instantaneously passed by applying a welding current in a state where a pressure is applied between the first workpiece and the pipe-shaped second workpiece. Is pushed into the cavity of the pipe-shaped second workpiece, and the protruding portion of the first workpiece is Providing ring mash welding method for joining the inner peripheral surface of the distal end portion of the pipe-shaped second weld object of.
In a fifth aspect based on the fourth aspect, when the pipe-shaped second workpiece is thin, the one welding electrode has a lower end surface of the pipe-shaped second workpiece. The present invention provides a ring mash welding method in a position substantially aligned with the lower end surface.
According to a sixth invention, in the first invention or the fifth invention, the protrusion of the first work piece is formed by pressing from the back side of the first work piece. A mash welding method is provided.

  According to the first to third aspects of the present invention, if ring mash welding is performed as it is, a thin pipe-shaped workpiece to be deformed or distorted may be deformed or distorted. In addition, the welded portions can be deeply engaged with each other, and can be reliably joined with a large joining strength.

According to the fourth to sixth inventions, even if one work piece is flat, the other pipe-like work piece is largely joined by forming a protrusion in advance by pressing or the like. Ring mash welding can be reliably performed with strength.

[Embodiment 1]
First, in describing a ring mash welding method according to an embodiment of the present invention, an example of a ring mash welding apparatus for realizing the present invention will be described with reference to FIG. In FIG. 1, AC power from an AC power source 1 such as a commercial AC power source or an AC generator is a rectifier circuit composed of a control type switch or a diode, or a rectifier circuit and a transformer that transforms the AC voltage into a predetermined voltage. It is converted into DC power by the DC power supply circuit 2 and the capacitor 3 made up of a plurality of electrolytic capacitors connected in parallel is charged. The switching circuit 4 such as a semiconductor switch or an inverter circuit discharges the electric energy stored in the capacitor 3 as a current pulse having a steep waveform. The current pulse is transmitted through the welding transformer 5 having the primary winding N1 having a larger number of turns than the secondary winding N2 and the secondary winding N2 having one or two turns. Flows through the first welding electrode 6, the second welding electrode 7 connected to N 2, and the first and second workpieces 8 and 9 that are pressed against each other by the first welding electrode 6, the second welding electrode 8, and the second welding electrode 8. The objects 8 and 9 are ring-mash welded.

  The ring mash welding method of Embodiment 1 is demonstrated using FIG.1 and FIG.2. 2A is a partial cross-sectional view for explaining the first and second workpieces 8 and 9, and FIG. 2B is the second welding electrode 7 and the second workpiece. 9 is a diagram for explaining the relationship with FIG. The first workpiece 8 is a metal member having a flat surface, and an empty portion 8a is formed on the flat surface. The hollow portion 8a may be a through hole or a concave portion having a bottom portion, but is formed so as to have an inner diameter D somewhat smaller than the outer diameter d of the pipe-like second workpiece 9 to be welded. Must have been. One half of the difference (d−D) between the inner diameter D of the hollow portion 8a and the outer diameter d of the pipe-shaped second workpiece 9 is the overlap margin of the entire circumference. Since this overlap margin is as described in Patent Document 1, description thereof is omitted.

  In the present invention, the second work piece 9 is a thin pipe-shaped member. In particular, the second work piece 9 is held by the second welding electrode 7 in order to perform ring mash welding as it is. The present invention is effective for ring mash welding of a thin-walled pipe-like metal tube having a thickness that distorts as described above when a necessary pressure is applied. Prior to welding, the reinforcing member 10 is attached to the tip of the hollow portion 9a of the second pipe-like workpiece 9 to be welded. A mounting portion 9b is provided at the tip of the pipe-shaped second workpiece 9 and when the pipe-shaped second workpiece 9 has a circular cross section, the mounting portion 9b and the reinforcing member 10 are provided. Also, the inner diameter of the mounting portion 9b and the outer diameter of the reinforcing member 10 are substantially the same, and the reinforcing member 10 is mounted on the mounting portion 9b with a slight force.

  The reinforcing member 10 is preferably a metal plate having the same shape as the cross-sectional inner side shape of the pipe-shaped second workpiece 9. Therefore, when the pipe-shaped second workpiece 9 is not circular but has a polygonal shape such as a quadrangular shape or a pentagonal shape, the reinforcing member 10 preferably has the same polygonal shape. Further, the reinforcing member 10 does not need to be a plate that is not formed with holes or the like and is entirely closed, and is formed with an annular or polygonal annular metal plate with a hole formed in the center, or a plurality of holes. However, the reinforcing member 10 does not come off due to the applied pressure during ring mash welding, and the mechanical strength of the pipe-shaped second workpiece 9 is not distorted. ing. However, the reinforcing member 10 does not necessarily have to be a metal plate, and may be a synthetic resin plate or a wooden plate that can satisfy the mechanical strength. In particular, the auxiliary plate 10 must be removed from the pipe-shaped second workpiece 9 later. In some cases, it is preferable to use a synthetic resin plate or wood plate that hardly welds. Moreover, in the case of a synthetic resin board or a wooden board, since the heat | fever generate | occur | produced at the time of welding is hard to be transmitted, it is preferable also from a welding viewpoint.

  In ring mash welding, it is described in Patent Document 1 that either one of the welded portions of the first and second workpieces is preferably a tapered surface at an angle, which is also shown in FIG. However, in this embodiment, the tip of the outer peripheral surface of the pipe-shaped second workpiece 9 is scraped at a certain angle to form a tapered surface 9c. The taper surface 9c is brought into contact with a substantially perpendicular circumferential angle formed by the inner circumferential surface forming the void 8a of the first workpiece 8 and the flat surface, and the circumferential angular portion functions as a projection. Since the welding current concentrates on the circumferential corner, ring mash welding can be performed with a relatively small welding current.

  In ring mash welding, the second welding electrode 7 holds the pipe-shaped second workpiece 9 in which the reinforcing member 10 is mounted in advance on the mounting portion 9 b. The welding electrode 7 is divided into two electrode parts 7A and 7B in the vertical direction, and the electrode-like parts 7A and 7B hold the pipe-shaped second workpiece 9 from both sides along its length direction. The welding electrode 7 is lowered while the pipe-shaped second workpiece 9 is gripped, and the tip of the pipe-shaped second workpiece 9 contacts the empty portion 8a of the first workpiece 8. In contact with each other, the overlap margin becomes almost equal. At this time, if necessary, the first workpiece 8 is moved back and forth in the drawing on the welding electrode 6 with an alignment member (not shown) so that the overlap margin is substantially uniform over the entire circumference. You may align the front-end | tip part of the pipe-shaped 2nd to-be-welded object 9 in the empty part 8a.

  In a state where the alignment is performed, the welding electrode 7 is pushed downward by a pressurizing mechanism (not shown), and a predetermined pressure is applied between the first and second workpieces 8 and 9. The electric energy accumulated in the capacitor 3 shown in FIG. 1 is discharged in a short time by the switching circuit 4, and a pulsed welding current is passed through the welded portion between the workpieces 8 and 9. This pulsed welding current flows in a concentrated manner in a narrow contact portion between the workpieces 8 and 9 and softens instantaneously, and with the progress of the softening, the pipe-shaped second workpiece is welded. 9 enters the empty portion 8a of the first workpiece 8 to be welded. In this way, the distal end portion of the pipe-like second workpiece 9 enters partway through the empty portion 8a of the first workpiece 8, and is joined, that is, ring mash welded, almost all around its circumference. . At this time, since the reinforcing member 10 exists, the distal end portion of the pipe-shaped second workpiece 9 is not crushed or distorted, and a good ring mash welding result can be obtained. In the case where the reinforcing member 10 is made of a metal plate, the reinforcing member 10 is also joined to the inner peripheral surface of the pipe-shaped workpiece 9 so that it does not come off. However, when the reinforcing member 10 is a synthetic resin plate or a wooden board, the reinforcing member 10 is easily detached due to the influence of heat by performing a tempering process or the like described in Patent Document 1. If necessary, it is possible to remove the reinforcing member 10 by applying a downward force in the drawing with a rod or the like through the cavity 9a of the pipe-shaped workpiece 9.

  In the first embodiment, when the welding electrode 7 comes into contact with the welding electrode 6, an electrical short circuit occurs and the welding electrodes 6 and 7 are damaged. Therefore, the welding electrode 7 has a pipe shape so as not to be short-circuited. The bottom end of the workpiece 9 is not covered. That is, since the lower surface 7 of the welding electrode 7 depends on the strength of the pipe-shaped workpiece 9 and the magnitude of the applied pressure during welding, it cannot be determined unconditionally, but it is 1 to 7 mm above its lower end. Preferably it is in position. Even if the reinforcing member 10 is provided at the distal end portion of the pipe-shaped workpiece 9, if the lower surface 7 of the welding electrode 7 is far away from the lower end portion of the pipe-shaped workpiece 9, the pipe-shaped workpiece 9 is en route. The weld 9 may be deformed or distorted. Therefore, in order to ensure that the thinner pipe-shaped workpiece 9 is not deformed or distorted, the reinforcing member 10 has a thickness of 1 to 7 mm or more, and the pipe-shaped workpiece to which the reinforcing member 10 is located. It is preferable that the welding electrode 7 extends and is gripped to a position below the outer peripheral surface corresponding to the inner peripheral surface 9.

  In addition, when the cross-sectional shape of the pipe-shaped second workpiece 9 is not a circular shape but a polygon such as a quadrangle or a pentagon, the space 8a of the first workpiece 8 is similarly rectangular or A polygon such as a pentagon is preferable. Further, if necessary, the outer peripheral surface of the second pipe-like workpiece 9 that is partially pipe-contacted with the inner peripheral wall that forms the space 8a of the first workpiece 8 instead of the entire circumferential surface. It may be mash welded.

[Embodiment 2]
The ring mash welding method of Embodiment 2 is demonstrated using FIG. In FIG. 3, the same symbols as those used in FIG. 2 indicate members having the same names. In the second embodiment, a protruding portion 8b is formed in advance on a flat portion of the first workpiece 8 by pressing, and the protruding portion 8b is formed into a cylindrical cavity 9a of the pipe-shaped second workpiece 9. It is characterized by mash welding on the inner surface. According to this embodiment, the metal pipe can be easily ring-mash welded to the metal plate by forming the protruding portion on the flat metal plate with a press.

  As shown in FIG. 3 (B), a flat portion of the first workpiece 8 is placed on a mold base 21 having a recess 20 and pressed from above by a press member 22 so that the first press pressed by the press member 22 is performed. The lower side of the flat portion of one work piece 8 is pushed out into the concave portion 20 of the mold table 21, and the upper side is recessed by that amount, so that a recess 8 c is formed. If the pipe-shaped second workpiece 9 has a cylindrical hollow portion 9a, the concave portion 20 of the mold base 21 overlaps more than the diameter h of the hollow portion 9a of the second workpiece 9 to be welded. It is of a short cylindrical shape having a large diameter H and preferably a depth of 1 to 5 mm. And the inner wall surface and bottom face of the recessed part 20 of the type | mold base 21 cross | intersect by arc shape or inclination. Therefore, the protrusion 8b formed on the flat portion of the first workpiece 8 in this way has an outer diameter that is substantially the same as the diameter H of the recess 20 of the mold base 21, and preferably a height of 1 to 5 mm. Moreover, the outer peripheral surface m and the upper surface n of the protrusion 8b intersect with each other in an arc shape or an inclined surface, and constitute a part of the overlap allowance.

  The welding electrode 7 is divided into two parts as shown in FIG. 2, or equally divided into three parts or four parts, and the diameter is enlarged or reduced, that is, the diameter is increased or decreased. The pipe-shaped second workpiece 9 is gripped or released with equal force. When the pipe-like second work piece 9 is thin like the above-described embodiment, the lower end surface 7a of the welding electrode 7 is substantially aligned with the lower end face 9c of the second work piece 9. Alternatively, it is preferable to hold the second workpiece 9 so as to be positioned slightly above. By gripping in this way, the pipe-shaped second workpiece 9 is not deformed or distorted by the applied pressure during welding. However, if the pipe-shaped second workpiece 9 is deformed or has a thickness that does not distort due to the pressure applied during welding without paying such attention, the welding electrode 7 is pipe-shaped. The upper part of the second workpiece 9 may be gripped.

  Thus, in a state where the second workpiece 9 is gripped, the welding electrode 7 is lowered or the welding electrode 6 is raised, and the first workpiece 8 is inserted into the cavity 9a of the second workpiece 9. The protrusions 8b are combined, and the inner peripheral end corners of the second workpiece 9 are brought into contact with the arcuate or inclined portions of the protrusions 8b and pressed. At this time, before the inner peripheral end corner portion of the second workpiece 9 contacts the arcuate or inclined portion of the protruding portion 8b, the overlap margin is substantially uniform over the entire circumference as necessary. With a positioning member (not shown), the first workpiece 8 is moved left and right and back and forth in the drawing on the welding electrode 6, and the tip of the pipe-shaped second workpiece 9 is aligned with the empty portion 8a. May be. When a pulsed welding current is passed between the welding electrodes 6 and 7 in a pressurized state, the protrusion 8b of the first workpiece 8 and the inner peripheral end corner of the second workpiece 9 The welding current concentrates on the abutting portion and instantaneously softens the abutting portion. As the softening progresses, the protruding portion 8c of the first workpiece 8 is a pipe-shaped second. It penetrates into the hollow portion 9a of the workpiece 9 to be welded. In this way, the protruding portion 8c of the first workpiece 8 enters the hollow portion 9a of the pipe-like second workpiece 9, and is joined, that is, ring mash welded, almost all around its circumference. .

  At this time, the tip surface 9c of the pipe-shaped second workpiece 9 does not necessarily reach the flat surface 8d of the first workpiece 8, but the tip of the pipe-shaped second workpiece 9 It is preferable from the viewpoint of production efficiency and welding strength that the surface 9c almost reaches the flat surface 8d of the first workpiece 8 to be welded. At this time, the lower end surface 7a of the welding electrode 7 is in contact with the flat surface 8d of the first workpiece 8, but the pulsed welding current has almost flowed up to that point, and a slight current is present at the contact stage. Since the contact area is much larger than the welding area, there is no problem at all.

In addition, when the cross-sectional shape of the cavity 9a in the pipe-shaped second workpiece 9 is not a circular shape but a polygon such as a quadrangle or a pentagon, the protruding portion 8c of the first workpiece 8 is the same. In addition, a polygon such as a quadrangle or a pentagon is preferable. In addition, if necessary, the inner peripheral surface of the partially welded pipe 9 and the protruding portion 8c of the first welded object 8 may be mash welded instead of the entire peripheral surface.

It is a figure which shows the outline | summary of the welding apparatus for implement | achieving the ring mash welding method which concerns on this invention. It is a figure for demonstrating the ring mash welding method of Embodiment 1 which concerns on this invention. It is a figure for demonstrating the ring mash welding method of Embodiment 2 which concerns on this invention. It is a figure for demonstrating the conventional ring mash welding method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Commercial AC power supply 2 ... DC power supply circuit 3 ... Capacitor 4 ... Switching circuit 5 ... Welding transformer 6 ... Welding electrode 7 ... Welding electrode 7a ... of welding electrode 7 Lower end surfaces 7A, 7B... Two parts 8 of welding electrode 7... First welded object 8 a... Empty portion 8 b of first welded object 8. 8c ··· flat portion 9 of first workpiece 8 ··· second pipe-like workpiece 9a · · hollow portion 9b of second pipe-like workpiece 9 ··· second pipe shape Mounting portion 9c of workpiece 9 to be welded ··· Tapered surface 9d of workpiece 9 to be welded second pipe · · Tip surface 10 of workpiece 9 to be welded second pipe · · Reinforcing member

Claims (6)

A tip portion of a pipe-like second workpiece having at least a part of the outer shape of the first workpiece having an inner circumferential surface that defines a hollow portion, the outer shape of which is at least partially larger than the hollow portion. In the mash welding method of welding the outer peripheral surface of
A reinforcing member is attached to the cavity at the tip of the pipe-shaped second workpiece,
The pipe-shaped second work piece is gripped by one welding electrode, and the pipe-like second work piece is placed in an empty portion of the first work piece supported by the other welding electrode. The tip part is overlapped with the overlap margin,
A welding current is applied in a state where a pressure is applied between the first workpiece and the pipe-shaped second workpiece, and the pipe is instantaneously inserted into the empty portion of the first workpiece. The tip of the second workpiece to be welded is pushed in to join the inner peripheral surface of the first workpiece to be welded and the outer peripheral surface of the tip of the pipe-like second workpiece to be welded. A ring mash welding method characterized by that. In claim 1,
The ring mash welding method, wherein the reinforcing member is a closed plate having a contour that fits the cavity, a plate having a hole, or a cylindrical body. In claim 1 or claim 2,
The ring mash welding method, wherein the one welding electrode extends to an outer position corresponding to an inner position of the pipe-shaped second workpiece to be applied to the reinforcing member. In the mash welding method of welding the first workpiece and the tip of the pipe-shaped second workpiece having a cavity,
Protruding portions having a diameter larger than the diameter of the inner peripheral surface forming the cavity at the tip of the pipe-shaped second workpiece are formed on the first workpiece.
One welding electrode grips the pipe-shaped second workpiece, and the pipe-shaped second workpiece is supported on the protruding portion of the first workpiece supported by the other welding electrode. The inner peripheral surface is overlapped with an overlap margin,
A welding current is applied in a state where a pressure is applied between the first workpiece and the pipe-shaped second workpiece, and the protruding portion of the first workpiece is instantaneously connected to the pipe. The second workpiece to be welded is pushed into the cavity of the second workpiece, and the projecting portion of the first workpiece to be welded and the inner peripheral surface of the tip of the second workpiece to be welded are joined. A ring mash welding method characterized by: In claim 4,
When the pipe-shaped second workpiece is thin, the one welding electrode has a lower end surface that is substantially aligned with a lower end surface of the pipe-shaped second workpiece. Ring mash welding method. In claim 4 or claim 5,
The ring mash welding method, wherein the protruding portion of the first workpiece is formed by pressing from the back side of the first workpiece.

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