JPH0710857Y2 - Workpiece holding member for butt resistance welding machine - Google Patents

Description

[Detailed description of the device]

[Industrial applications]

The present invention relates to a work holding member used in a butt resistance welding machine such as a butt welding machine or a flash welding machine to supply a welding current to a welding work and hold each work to press a joining surface.

[Prior art]

Conventionally, the butt welder and the flash welder described above are known as butt resistance welders, and the welding method in the butt welder will be described with reference to FIGS. 10 to 13. FIG. 10 is a front view of the work holding portion with the welded work 11 set, FIG. 11 is a right side view of the work holding part, and FIG. 12 is a plan view of the work holding part with an electric circuit added. In the figure, 1 is a fixed electrode which also serves as a work holding member, and 2 is a moving electrode which also serves as a work holding member and which moves to the left and right by an air cylinder or the like, and these are vertically divided into two parts. The upper electrodes 3 and 4 and the lower electrodes 5 and 6 are fixed to the upper electrode holders 7 and 8 and the lower electrode holders 9 and 10, respectively, and although not shown, the upper electrodes 3 and 4 are, for example, air cylinders. By moving up and down by expansion and contraction of the hydraulic cylinder, holding and release of the work 11 between the lower electrodes 5 and 6 is controlled. Further, as shown in FIG. 12, a large current is supplied from the electrodes 1 and 2 to the work 11 via the transformer 16. FIG. 13 is a front view of the work holding portion at the stage of setting the work 11, but the work 11 is placed on each of the lower electrodes 5 and 6 and then each of the upper electrodes 3 as shown in this figure. , 4 are pressed to the lower electrode sides 5, 6 to be held by the electrodes 1, 2 as shown in FIG. Then, the moving electrode 2 is fixed to the fixed electrode 1.
The joint surface of the work is pressed by urging it to the side, and a welding current is applied in that state to press the joint surface to a high temperature, and the respective works are joined. At this time, the joint part melted by high heat is pushed out of the work and deforms, so that a so-called burr is generated, so that the moving electrode 2 approaches the fixed electrode 1. However, the approaching amount, that is, the deviation is set to an appropriate value. By controlling the welding conditions such as welding current, energizing time, pressure, etc., stable welding quality of the joint, which is reflected in the strength and overall dimensions of the product, is secured.

[Problems to be solved by the device]

By the way, when welding with this butt resistance welding machine,
There is a case where slippage occurs between the work 11 and the electrodes 1 and 2 and the joint is not strongly pressed. In such a case, the energization and contact resistance become unstable and the part is not melted sufficiently, so a predetermined margin cannot be obtained, and as a result, good welding quality such as sufficient strength of the joint is obtained. I can't. Such poor welding occurs when the holding force of the work, that is, the pressing force of the upper electrode is too weak with respect to the pressing force of the joint surface, when oil or the like is attached to the contact surface between the work and the electrode, and This may occur when the contact area between the electrode and the electrode is insufficient. On the other hand, in order to eliminate the slippage of the work, it is sufficient to prevent the adhesion of oil or the like on the contact surface, eliminate the shortage of the contact area, and increase the pressing force of the upper electrode. In some cases, the pressing mechanism or the frame of the welding machine must be made large in order to increase the pressing force. Further, a member for urging only the work may be separately provided in order to pressurize the joint surface, but this would complicate the configuration. The present invention was created in order to effectively solve the above-mentioned conventional technical problems of the present invention. Therefore, the purpose thereof is to prevent slippage between the electrode and the work, which may occur even in butt resistance welding, with a very simple structure, and to improve the quality of the joint portion of the work.

[Means for Solving the Problems]

The work holding member of the butt resistance welding machine according to the present invention is configured as follows to achieve the above object. That is, a work holding member used for holding a welding work in a butt resistance welding machine and supplying a welding current to the welding work, and a first electrode and a second electrode that cooperate with each other to hold the welding work. , A work fixing member configured to be positionally fixed with respect to at least one of the two electrodes, and the work fixing member has locking projections protruding toward the work side from a contact surface of each electrode with the work. The locking protrusion is formed of a material having a hardness higher than that of the work and has a sharp shape.

[Action / effect]

When the work holding member having the above configuration is applied to, for example, a butt welding machine, when the work is held between the first electrode and the second electrode when the work is held, first, the welding is performed from the contact surface of the electrode with the work. The locking protrusion of the workpiece fixing member that protrudes toward the workpiece contacts the surface of the workpiece, and
Since the locking projections are made of a material having a hardness higher than that of the welding work and are formed into a sharp shape, the surface of the welding work is gradually deformed and enters the inside of the welding work. Then, when the contact surface of the electrode with the work comes into contact with the welded work, the locking projections are locked with the welded work,
Each electrode securely holds the welding work. At the time of welding, these work holding members provided with electrodes and work fixing members are urged to approach each other to press the joining surface of the works,
Since the electrode and the work fixing member are positionally fixed and the locking projections of the work fixing member are locked to the work, the relative positional relationship between the welding work and the work holding member does not change. Therefore, according to the above-mentioned configuration, the contact surface and the energized state are stabilized because the joint surface of the workpieces is sufficiently pressed, despite the extremely simple configuration, and the predetermined margin between workpieces is secured. can do. As a result, a product having stable and good welding quality such as strength, size, burr height and heat affected zone can be obtained. Further, since the work fixing member having the locking projections is provided separately from the electrode, only the locking projections can be replaced, for example, when the locking projections are worn, which is economical.

【Example】

The embodiments of the present invention shown in FIGS. 1 to 9 will be described in detail below. First, the work holding member of the butt resistance welding machine according to the first embodiment of the present invention shown in FIGS. 1 to 4 will be described. These drawings show a state in which a work holding member according to the first embodiment of the present invention holds a steel pipe having a circular cross section as a welding work 11 in a butt welding machine. 2 is a right side view and FIG. 3 is a plan view. In the figure, reference numeral 1 denotes a fixed electrode which also serves as a work holding member, and 2 denotes a moving electrode which also serves as a work holding member and which moves left and right by an air cylinder. Each electrode 1, 2
Are composed of upper electrodes (first electrodes) 3 and 4, lower electrodes (second electrodes) 5 and 6, upper electrode holders 7 and 8 and lower electrode holders 9 and 10, respectively. The point that the work 11 is held by the concave surface 18 formed in the same curvature as the work 11 by pressing the electrodes 3 and 4 against the lower electrodes 5 and 6 is the same as that already described as the conventional example. is there. In addition to the above configuration, in the present embodiment, the upper and lower electrodes 3, 4,
As shown in Figures 5 and 6, 3 each in a row along the center line of the work
Individually, a work fixing member 12 is incorporated. The work fixing member 12 is formed in the shape of a pin with a head, and through-holes 17 for inserting the work fixing member 12 are formed in the upper and lower electrodes 3, 4, 5 and 6 into which the work fixing member 12 is incorporated. There is. As shown in detail in FIG. 4, the work fixing member 12 is formed to be slightly longer than the thickness of each of the electrodes 3, 4, 5 and 6 as a whole, and its tip portion is a locking portion (locking protrusion). ) 13 is formed at an acute angle. Then, in the state where the upper electrodes 3 and 4 and the upper electrode holders 7 and 8 or the lower electrodes 5 and 6 and the lower electrode holders 9 and 10 are fixed, the work 11 on each electrode 3, 4, 5 and 6 is fixed. The engaging portion 13 is dimensioned to project from the contact surface, that is, the concave surface 18. In addition, this work fixing member 12
Is formed of a material having a hardness higher than that of the work, such as hardened steel, so as to bite into and lock the surface of the work when the work is held. In the butt welding machine using the work holding member configured as described above, that is, the fixed electrode 1 and the moving electrode 2, first, the work 11 is placed on the lower electrodes 5 and 6 with the upper and lower electrodes separated. The upper electrodes 3 and 4 are pressed to the lower electrodes 5 and 6 side. Upper electrodes 3, 4 are lower electrodes 5, 6
At the initial stage of being pressed to the side, the work 11 comes into contact with the engaging portion 13 at the tip of the work fixing member 12. After that, the locking portion 13 gradually bites into the surface of the work 11, and eventually the work 11 and the concave surfaces (contact surfaces) 18 of the electrodes 3, 4, 5 and 6 come into contact with each other, so that the locking portion 13 is locked to the work 11. Each electrode 1 and 2 is work 11
Hold securely. As described above, when the electrodes 11 and 2 securely hold the work 11, the movable electrode 2 is biased toward the fixed electrode 1 to sufficiently press the joint surface of the work. Therefore, if welding current is supplied in that state, the joint surface is sufficiently heated by the contact resistance and melted. Since the joint surface is pressurized even when it reaches a predetermined temperature, the melted joint portion is extruded outward and burrs are formed, so that an appropriate margin is obtained. As a result, it is possible to obtain a product having a sufficient weld quality such as sufficient strength and a predetermined size. Further, the work fixing member 12 has a structure in which each electrode 3, 4, 5,
It can be easily replaced by disassembling 6 and the electrode holders 7, 8, 9, 10. Next, the work holding member according to the second embodiment of this embodiment shown in FIGS. 5 to 9 will be described below. Each drawing shows a state in which the work holding member according to the second embodiment of the present invention holds a steel pipe having a circular cross section as the welding work 11 in the butt welding machine as in the first embodiment.
The drawing is a central longitudinal sectional view, FIG. 6 is a plan view, and FIG. 7 is a right side view. As shown in the figure, in the present embodiment, a work fixing member 14 having an L-shaped cross section is sandwiched between each electrode 3, 4, 5, 6 and the electrode holder 7, 8, 9, 10. ing. The work fixing member 14 has the work 11 as shown in FIG. 9 showing its details.
Locking part (locking protrusion) consisting of three protrusions on the contact surface side with
15 is formed, and the locking portion 15 is sandwiched between the electrodes 3, 4, 5 and 6 and the electrode holders 7, 8, 9 and 10, and is used as a work for the electrodes 3, 4, 5 and 6. Sized to project slightly from the contact surface of the. The locking portion 15 can be formed in a linear shape as shown in FIG. 7 or an arc shape along the contact surface between the electrode and the work as shown in FIG. 8 showing a modified example. Even in this configuration, since the locking portion 15 bites into and locks the work surface when holding the work, as in the first embodiment,
Each of the electrodes 1 and 2 reliably holds the work 11 as a work holding member. Therefore, the joining surface is surely pressed under the set welding conditions, and as a result, a product having sufficient welding quality such as sufficient strength and predetermined dimensions can be obtained. . Further, the work fixing member 14 can be easily replaced. In the present embodiment, the work fixing members are provided on both the upper and lower electrodes, but the fixing members are made larger and the locking portions (protrusions) thereof are provided.
When the number of the above is increased, the fixing member and the locking portion thereof may be provided only on one of the upper side electrode and the lower side electrode. In this case, the same effect can be obtained. In each of the above-mentioned embodiments, the indentation is formed on the surface of the work where the engaging portion bites, but since this is extremely fine, there is no problem in terms of the strength of the work. Further, although the work is described as a steel pipe having a circular cross section in each of the above-described embodiments, the shape of the work is not limited to such a straight rod-shaped member having a circular cross section, and needless to say, it can be applied to various other shapes. Further, the present invention does not limit the shape of the locking portion and the number of protrusions in the fixing member.

[Brief description of drawings]

1 to 4 show a work holding member of a butt resistance welding machine according to a first embodiment of the present invention. FIG. 1 is a central longitudinal sectional view in a state where a work is held, and FIG. 2 is a right side surface. Figure,
FIG. 3 is a plan view, FIG. 4 is an enlarged view of an essential part, and FIGS.
FIG. 5 shows a work holding member of a butt resistance welding machine according to a second embodiment of the present invention. FIG. 5 is a central longitudinal sectional view with a work held, FIG. 6 is a plan view, and FIG. 7 is a right side. FIG. 8 is a sectional view of a main part, FIG. 9 is a right side view of a work holding member according to a modification, and FIGS. 10 to 13 are work holding members of a butt resistance welding machine according to a conventional example. Fig. 10 is a front view of the work while it is held, Fig. 11 is a right side view, Fig. 12 is a plan view schematically showing an electric circuit, and Fig. 13 is a work at the stage of setting the work. It is a front view which shows a holding member. 1 ... Fixed electrode (work holding member), 2 ... Moving electrode (work holding member), 3,4 ... Upper electrode (first electrode), 5,6 ... Lower electrode (second electrode), 7,8 ... Upper side Electrode holder, 9,10 ... Lower electrode holder, 11 ... Welding work, 12,14 ... Work fixing member, 13,15 ... Locking part (locking protrusion), 16 ... Transformer, 17 ...
Through hole, 18… Concave surface (contact surface)

Claims (1)

[Scope of utility model registration request] 1. A work holding member (1, 2) used for holding a welding work (11) and supplying a welding current to the work (11) in a butt resistance welding machine, in cooperation with each other, A first electrode (3, 4) and a second electrode (5, 6) for sandwiching a welding work (11), and both electrodes (3, 4)
A work fixing member (12, 14) configured to be positionally fixed to at least one of (5, 6), and the work fixing member (12, 14) is provided for each electrode (3, 4). The locking projections (13, 15) protruding toward the work (18) side from the contact surface (18) with the work (11) at (5, 6) are provided with the locking projections (13, 15). A work holding member for a butt resistance welding machine, wherein the work holding member is formed of a material having a hardness higher than that of the work (11) and has a sharp shape.