JP2018149590A - attachment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an attachment simply attachable to/detachable from an electrode so that excellent spot welding free from spot bruise and spot welding of a fine part can be compatible with each other, in a single spot welding apparatus.SOLUTION: An attachment 6 fitted to a first electrode 4 of a spot welding apparatus 10 includes an electrode insertion ring 12 into which the first electrode 4 is inserted, and an attachment body 11 formed on a position on the opposite side to a position where the first electrode 4 is inserted, and having a flat surface having a larger diameter than the tip of the first electrode 4. The electrode insertion ring 12 has an insulation ring 13 fitted externally to the first electrode 4, and a fixing bolt 14 for reducing the diameter of the insulation ring 13.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a spot welding apparatus that performs spot welding by sandwiching a member to be welded between a pair of electrodes.

  Conventionally, in this type of spot welding apparatus, a plurality of members to be welded are overlapped, the tip of one electrode is brought into contact with one surface of the member to be welded, and the back surface of one surface of the member to be welded is contacted. The member to be welded is sandwiched between the pair of electrodes by contacting the tip of the other electrode. A predetermined current is passed between the electrodes and the welded parts are melted by resistance heat generated in the welded members to join the welded members (for example, see Patent Document 1).

JP 2009-72796 A

  In the spot welding apparatus described in Patent Document 1, the welded portion is melted during spot welding to generate a molten pool, and the molten pool melt is surrounded by the pressure applied to each tip of the electrode. I will run away. Therefore, the welded portion of the member to be welded is recessed, and so-called spot dents are generated in which burrs are generated around the recess. A spot dent is not preferable in appearance and has a poor touch. In order to remove spot dents, it is necessary to first remove burrs with a cutting tool, fill the dents with a filling member, so-called sheet metal putty, and perform a polishing operation to flatten the surface.

  In order to prevent the generation of spot dents, it is conceivable to perform spot welding with a pair of electrodes having different shapes. For example, it is conceivable to perform spot welding with a spot welding apparatus provided with a large electrode whose tip surface is processed flat and a small electrode with a small diameter at the tip.

  In this spot welding apparatus, since the contact surface of the large electrode is wider than the contact surface of the small electrode, the entire molten pool and its periphery generated during spot welding are subjected to pressure at the tip of the large electrode, The melt does not escape around the welded portion, and the occurrence of spot dents is prevented. In this spot welding apparatus, good spot welding without spot dents can be obtained.

  On the other hand, some spot welding apparatuses equipped with large electrodes have a structure in which spot welding cannot be performed due to interference between members and parts positioned around the joint portion of the member to be welded and the large electrodes. In such a small part that cannot be spot welded and has a structure that allows the generation of spot dents, interference will occur if both are spot welded with a conventional spot welding device equipped with a small electrode. It is possible to perform spot welding of fine details.

  However, a spot welding device equipped with both a large electrode and a small electrode, and a spot welding device equipped with a small electrode for both, are installed, and the spot welding device is properly used according to the structure of the welded part of the member to be welded. However, there is a problem that a different spot welding apparatus has to be installed, and the efficiency of the work is lowered. With a single spot welding apparatus, there is a problem that it is impossible to achieve both good spot welding without spot dents and spot welding of fine portions.

  The present invention has been made to solve such problems, and it is possible to achieve both good spot welding without spot dents and fine spot welding with a single spot welding apparatus. Thus, it is an object to provide an attachment that can be easily attached to and detached from an electrode.

The attachment of the present invention that solves the above problems is as follows.
An attachment attached to the tip of a resistance welding device tip,
An insertion part into which the chip is inserted;
A contact portion that is formed at a position opposite to the position where the chip is inserted and has a flat surface with a diameter larger than the tip of the chip;
With
The insertion portion includes an insulating ring that is externally fitted to the chip, and a fixing bolt that reduces the diameter of the insulating ring.

  With this configuration, the contact portion has a flat surface having a diameter larger than that of the tip of the tip, so that no spot dent is generated during spot welding. The entire molten pool generated in spot welding and the periphery thereof are subjected to pressure at the member abutting portion, so that the molten material does not escape around the welded portion, thereby preventing the occurrence of spot dents.

  Further, the attachment can be easily and reliably fixed to the chip by reducing the diameter of the insulating ring with a fixing bolt. On the other hand, the attachment can be easily detached from the chip by releasing the diameter reduction of the insulating ring by the fixing bolt.

  Further, since the insulating ring electrically insulates between the tip and the fixing bolt, it is possible to prevent discharge from the tip to the contact portion via the fixing bolt, and so-called reactive current can be prevented from being generated.

  According to the present invention, an attachment that can be easily attached to and detached from an electrode so that good spot welding without spot dents and spot welding of fine portions can be made compatible with a single spot welding apparatus. Can be provided.

The side view which shows a part of spot welding apparatus equipped with the attachment which concerns on embodiment of this invention. The partial side view which expanded the mounting part of the attachment which concerns on embodiment of this invention. The perspective view of the attachment concerning the embodiment of the present invention. The disassembled perspective view of the attachment which concerns on embodiment of this invention. Sectional drawing of the attachment which concerns on embodiment of this invention. The figure explaining the attachment of the spot welding apparatus of a prior art. The figure explaining the effect | action of a structure without an insulating ring with the attachment which concerns on embodiment of this invention.

  An embodiment in which an attachment according to the present invention is applied to a spot welding apparatus 10 which is one of resistance welding apparatuses will be described with reference to the drawings.

  As shown in FIG. 1, the spot welding apparatus 10 includes a welding gun body 1, a C-shaped C-shaped arm 2, a second electrode 5 fixed to the C-shaped arm 2, and a second electrode 5. The first electrode 4 is disposed at an opposing position, the moving mechanism 3 is configured to reciprocate the first electrode 4 in a direction approaching or separating from the second electrode 5, and the attachment 6 is fixed to the first electrode 4. The

  The welding gun body 1 is mounted on a moving device such as a robot (not shown) and moved by the moving device, and is positioned so that the welded portion of the member W to be welded is positioned between the first electrode 4 and the second electrode 5. It has become so. The C-arm 2 is provided on the welding gun body 1 and can move relative to the welding gun body 1.

  The moving mechanism 3 is provided in the welding gun body 1 and reciprocates with respect to the second electrode 5 fixed to the C-shaped arm 2 so that the first electrode 4 approaches or separates. Further, as shown in FIG. 2, the moving mechanism 3 moves the first electrode 4 to sandwich the member W to be welded between the second electrode 5 and applies a predetermined pressure to the member W to be welded. It has become.

  As shown in FIG. 2, the first electrode 4 has a cylindrical main body 4a and a front end 4b formed integrally with the main body 4a and having a tip formed in a curved shape, for example, a hemisphere. ing. The first electrode 4 is made of a material having good conductivity, for example, copper.

  Similar to the first electrode 4, the second electrode 5 has a cylindrical main body portion 5a and a front end portion 5b formed integrally with the main body portion 5a and having a tip formed in a curved shape, for example, a hemisphere. ing. Similar to the first electrode 4, the second electrode 5 is made of a material having good conductivity, such as copper.

  As shown in FIG. 1, the second electrode 5 is fixed to the C-arm 2 so as to face the first electrode 4 so that the axis of the second electrode 5 overlaps with the axis X of the first electrode 4. Yes.

  The attachment 6 is attached to the tip of the first electrode (chip) 4 and is detachably attached to the first electrode 4 with a fixing bolt 14 as shown in FIGS. 1 and 2. As shown in FIG. 3, the attachment 6 includes an attachment main body 11 (contact portion), an electrode insertion ring (insertion portion) 12 into which the first electrode 4 is inserted, an insulating ring 13, and a fixing bolt 14. Is done.

  As shown in FIGS. 4 and 5, the attachment body 11 includes an electrode abutting portion 21 that abuts on the first electrode 4 and a member abutment that abuts on the member W to be welded on the opposite side of the electrode abutting portion 21 in the axial direction. The contact portion 22 and a holding portion 23 that holds the electrode insertion ring 12 are provided. The attachment body 11 is made of a material having good conductivity, for example, copper, like the first electrode 4, and has a mechanical strength that can withstand a predetermined number of spot weldings. The predetermined number of times is, for example, about 100 to 150 times.

  The electrode contact portion 21 is formed with a smooth and flat surface without unevenness so as to contact the first electrode 4. The member contact portion 22 is formed at a position opposite to the position where the first electrode 4 is inserted, and has a tip surface (flat surface) 22 a having a larger diameter than the tip of the first electrode 4. The distal end surface 22a is formed with an outer diameter D3 larger than the outer diameter D1 of the first electrode 4 and the outer diameter D2 of the second electrode, and is a smooth flat surface.

  As shown in FIG. 5, the tip end surface 22a abuts on the member W to be welded. The outer diameter D3 is formed with a predetermined dimension that does not generate spot dents, has less interference with the parts and surrounding structures arranged around the welded portion, and can be attached to the first electrode 4. The The predetermined dimension is, for example, about 35 mm.

  The member contact portion 22 is formed with a predetermined thickness t1 so as not to be deformed during spot welding. The predetermined thickness is, for example, about 15 mm. The holding portion 23 has an outer diameter smaller than the outer diameter D3 of the electrode contact portion 21 and is formed to protrude from the electrode contact portion 21. A holding hole 23 a is formed in the holding portion 23 in the axial direction so as to hold the electrode insertion ring 12.

  The electrode insertion ring 12 includes a cylindrical convex portion 31 and a fixing portion 32 that is formed integrally with the convex portion 31 and has an outer diameter larger than the outer diameter of the convex portion 31. The electrode insertion ring 12 is formed of a synthetic resin having flexibility and insulating properties. Examples of the synthetic resin include a nylon resin called NC nylon and a nylon resin called MC nylon (registered trademark).

  As shown in FIG. 5, when the convex portion 31 is inserted into the holding hole 23 a, the tip 31 a of the convex portion 31 hits the electrode contact portion 21 and faces the fixed portion 32 facing the tip of the holding portion 23. 32 a comes to abut against the tip of the holding portion 23. With this configuration, the convex portion 31 is firmly held by the holding portion 23. It should be noted that the convex portion 31 is firmly held between the outer peripheral surface of the convex portion 31 and the holding hole 23a by a bonding means such as an adhesive so that the convex portion 31 is more firmly held. May be.

  An insertion hole 31b for inserting the first electrode 4 is formed in the convex portion 31, and an insertion hole 32b having an inner diameter larger than that of the insertion hole 31b is inserted in the fixing portion 32. A step 32c is formed between the insertion hole 31b and the insertion hole 32b. Furthermore, a screw hole 32e that penetrates in the direction orthogonal to the axial direction of the electrode insertion ring 12 is formed in the side surface 32d of the fixing portion 32, and the fixing bolt 14 is screwed into the screw hole 32e.

  The insulating ring 13 has an insertion hole 13 a, and the first electrode 4 is inserted into the insertion hole 13 a and is externally fitted to the first electrode 4. The insulating ring 13 is inserted into the insertion hole 32b of the fixing portion 32, and when inserted, the front end surface 13b of the insulating ring 13 comes into contact with the step 32c.

  As shown in FIG. 5, the insulating ring 13 is inserted into the insertion hole 32 b of the fixing portion 32 and the first electrode 4 is inserted into the insertion hole 13 a of the insulating ring 13, that is, the outer periphery of the first electrode 4. When the fixing bolt 14 is screwed in a state where the insulating ring 13 is interposed between the surface 4c and the inner peripheral surface 32f of the insertion hole 32b of the fixing portion 32, the fixing bolt 14 causes the insulating ring 13 to be reduced in diameter. Due to elastic deformation, the first electrode 4 is firmly fixed to the fixing portion 32 via the insulating ring 13.

  The fixing bolt 14 is formed of a material having high mechanical strength, for example, a metal material. If the bolt 14 is configured so that the tip end portion 14a presses the insulating ring 13 by screwing, the shape of the fixing bolt 14 is particularly limited. It is not limited. For example, it is composed of a hexagon bolt having a hexagonal head.

  Operation | movement of the spot welding apparatus 10 which concerns on embodiment comprised as mentioned above is demonstrated easily.

  When the member to be welded W is set, a welding operation is started, and the welding gun body 1 shown in FIG. The attachment 6 attached to 4 is positioned, and positioning is performed so that the second electrode 5 is positioned on the other side of the welded portion of the member W to be welded.

  When the positioning is completed, the moving mechanism 3 operates to move the C-arm 2 to move the second electrode 5 in a direction in the vicinity of the member to be welded W and to contact the welded portion of the member to be welded W. Further, the moving mechanism 3 moves the first electrode 4, and the attachment 6 and the second electrode 5 cooperate to apply a predetermined pressure to the welded portion of the member W to be welded.

  In this state, a voltage is applied between the attachment 6 and the second electrode 5, and a welding current is passed between the attachment 6, the welded portion of the welded member W and the second electrode 5, and the welded member W The welded portion is spot welded.

  When the spot welding is completed, the moving mechanism 3 operates to move the first electrode 4 in a direction away from the member to be welded W. The welding gun body 1 shown in FIG. 1 is moved again by a moving device such as a robot, and the attachment 6 attached to the first electrode 4 is positioned on one side of the other welded portion of the welded member W. The second electrode 5 is positioned on the other side of the welded portion.

  When the positioning is completed, like the first spot welding, a predetermined pressure is applied to the other welded portions of the welded member W, a welding current is passed, and the other welded portions of the welded member W are spot welded. The Such an operation is repeated until there is no unwelded portion that is not spot-welded in the preset welded portion of the member W to be welded.

  The effect of the attachment 6 of the spot welding apparatus 10 according to the embodiment configured as described above will be described.

  According to the attachment 6 according to the embodiment, the member contact portion 22 of the attachment 6 attached to the first electrode 4 has an outer diameter D3 larger than the outer diameter D1 of the first electrode 4 and the outer diameter D2 of the second electrode 5. Since the front end surface 22a is formed in the above, spot dents are not generated during spot welding.

  Since the member abutting portion 22 of the attachment 6 has a grounding surface wider than the grounding surface that abuts on the member W to be welded of the second electrode 5, the entire molten pool and its periphery generated during spot welding are members. Pressure is received at the contact portion 22, and the melt does not escape around the welded portion, the occurrence of spot dents is prevented, and good spot welding can be obtained.

  As a result, it is not necessary to perform a finishing operation for removing spot dents that have occurred in the past, and the effect that the welded member W is efficiently spot welded can be obtained.

  The electrode insertion ring 12 is formed of a synthetic resin such as MC nylon (registered trademark) having flexibility. Therefore, even when the welded member W is set obliquely from a horizontal position perpendicular to the axis X of the attachment 6 and the second electrode 5 attached to the first electrode 4 shown in FIG. It deforms according to.

  As a result, the tip end surface 22a of the member contact portion 22 of the attachment 6 is brought into close contact with the member to be welded W without being obliquely contacted, so that there is an effect that good spot welding can be obtained.

  Further, since the attachment 6 is configured to be detachable from the first electrode 4 by the fixing bolt 14, the attachment main body 11 can be easily fixed to the first electrode 4 by tightening the fixing bolt 14.

  On the other hand, the attachment main body 11 can be easily detached from the first electrode 4 by loosening the fixing bolt 14. As a result, it can be easily attached to the electrodes of the welding gun main body of various spot welding apparatuses, and the versatility of the attachment 6 is improved.

  In addition, since the attachment 6 is configured to be detachable from the first electrode 4, the attachment 6 is attached to a portion where appearance is important in a single spot welding apparatus, and there is no spot dent. Good spot welding can be performed.

  On the other hand, as shown in FIG. 6, in the case of a welded part such as a door part of an automobile in which a structure is provided in the vicinity of the welded part, the attachment 6 may interfere with the structure. For such a fine welded portion, the attachment 6 can be removed and spot welding can be performed directly by the first electrode 4 and the second electrode 5.

  Further, since the outer diameter D3 of the member abutting portion 22 of the attachment 6 is formed at 35 mm and the thickness t1 is formed at 15 mm, good spot welding can be obtained and interference with parts and structures is reduced. The effect is obtained. As a result, it is possible to obtain an effect that it is possible to achieve both good spot welding without spot dents and fine spot welding with a single spot welding apparatus.

  Furthermore, since the insulating ring 13 is formed of a flexible nylon resin and is interposed between the electrode insertion ring 12 and the first electrode 4, the fixing bolt 14 is screwed into the electrode insertion ring 12. The insulating ring 13 is elastically deformed in the direction of reducing the diameter and is in close contact with the first electrode 4, so that the fixing portion 32 of the electrode insertion ring 12 is securely fixed to the first electrode 4.

  The convex portion 31 of the electrode insertion ring 12 is formed integrally with the fixing portion 32, and the convex portion 31 is firmly held by the holding portion 23 of the attachment body 11, so that the fixing bolt 14 is screwed into the electrode insertion ring 12. As a result, the effect that the attachment 6 is firmly attached to the first electrode 4 is obtained. That is, even if it is the attachment 6 which can be attached or detached simply, the effect that spot welding can be performed in the state in which the attachment 6 was firmly hold | maintained is acquired.

  Further, the structure different from the spot welding apparatus 10 according to the present embodiment, for example, as shown in FIG. 7, the insulating ring 13 is not provided, and the attachment 6 is directly fixed to the first electrode 4 with the fixing bolt 14. In the spot welding apparatus 20 having such a structure, there is a problem of a reactive current indicated by a so-called arrow a and a discharge to the atmosphere indicated by an arrow b.

When the second electrode 5 is energized from the first electrode 4 through the member contact portion 22 of the attachment body 11 and the member W to be welded, the member contact portion of the attachment body 11 from the first electrode 4 via the fixing bolt 14. The reactive current may be generated by this discharge.
Further, the first electrode 4 may discharge to the atmosphere via the fixing bolt 14.

  However, in the spot welding apparatus 10 according to the present embodiment, since the first electrode 4 and the fixing bolt 14 are electrically insulated by the insulating ring 13, the member contact is made from the first electrode 4 via the fixing bolt 14. The portion 22 is not discharged and no reactive current is generated. Further, there is no discharge from the first electrode 4 to the atmosphere via the fixing bolt 14. As a result, the effect of eliminating the problem of reactive current and discharge to the atmosphere can be obtained.

  Moreover, since the attachment 6 is attached to the first electrode 4 and not the second electrode 5 in the spot welding apparatus 10 according to this embodiment, the welding current is at one point where the second electrode contacts the member W to be welded. As a result, a good welding can be obtained, and a decrease in the efficiency of the welding current is suppressed.

  In the above-described embodiment, the case where the attachment 6 is applied to a C-type welding gun has been described as an example. However, the attachment 6 may be an X-type or a stationary spot welder.

  DESCRIPTION OF SYMBOLS 1 ... Welding gun main body, 2 ... C type arm, 3 ... Moving mechanism, 4 ... 1st electrode, 4a ... Main body part, 4b ... Tip part, 4c ... Outer peripheral surface, 5 ... 2nd electrode, 5a ... Main body part 5b ... tip part, 6 ... attachment, 10, 20 ... spot welding device, 11 ... attachment main body, 12 ... electrode insertion ring, 13 ... insulating ring, 13a ... insertion hole, 13b ... tip surface, 14 ... fixing bolt, 14a ... tip part, 21 ... electrode contact part, 21a ... flat surface, 22 ... member contact part, 22a ... tip face, 23 ... holding part, 23a ... holding hole, 31 ... convex part, 31a ... tip, 31b ... insertion Hole, 32 ... fixed portion, 32a ... opposing surface, 32b ... insertion hole, 32c ... step, 32d ... side surface, 32e ... screw hole, 32f ... inner peripheral surface, D1, D2, D3 ... outer diameter, t1 ... thickness, X ... Axis, W ... Welded member

Claims (1)

An attachment attached to the tip of a resistance welding device tip,
An insertion part into which the chip is inserted;
A contact portion that is formed at a position opposite to the position where the chip is inserted and has a flat surface with a diameter larger than the tip of the chip;
With
The attachment is characterized in that the insertion portion includes an insulating ring fitted on the chip and a fixing bolt for reducing the diameter of the insulating ring.

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