JP7522629B2 - Swivel type welding electrodes - Google Patents

Description

The present invention relates to a technology for enhancing the cooling effect on a rotating part at the tip of an electrode used for spot welding, etc., in which the rotating part at the tip of the electrode can rotate within a predetermined angle range relative to the axial direction of the base part at the base end.

The applicant has proposed a technology to reduce the effort and cost of replacing electrodes due to wear and tear during welding work such as spot welding by dividing the electrode into a tip portion that is subject to high wear and a durable base portion, and to use the base portion for a relatively long period of time compared to the tip portion, in order to eliminate the effort and cost of replacing electrodes due to wear and tear and to reduce running costs. (See, for example, Patent Document 1.)

Utility Model Registration No. 3212770

In this technology, as shown in FIG. 7, the swivel-type electrode 51 is formed by connecting the base part 52 at the base end of the electrode with the rotating part 53 at the tip end of the electrode by a swivel joint 54 having a spherical fitting part k, and the rotating part 53 is divided into a first divided body 53a at the tip end and a second divided body 53b at the base end. Even if the first divided body 53a, which is subject to heavy wear during welding work, is worn out, the second divided body 53b continues to be used, thereby reducing running costs and the effort and time required for replacement work. However, in this conventional structure, as shown in FIG. 7(b), the cooling water passage s is only provided in the base part 52, and no cooling water passage is formed in the rotating part 53, which is particularly subject to heavy wear, so the cooling effect on the first divided body 53a, which directly contacts the work and generates heat, is insufficient, and there is a problem with the durability of the first divided body 53a.

The present invention aims to improve the cooling effect on the rotating part at the tip of the electrode, which is particularly susceptible to heat generation and wear, and to further improve durability.

To achieve the above object, the present invention provides a swivel-type welding electrode in which a tip-side rotating part is joined to a base part on the base end side via a swivel joint having a spherical fitting part, the rotating part is divided into a first divided part on the tip end side and a second divided part on the base end side along the axial direction, and these first and second divided parts can be joined via any joining structure, and the base part and the second divided part are joined together via a swivel joint. A cooling water supply passage for cooling the electrode is formed along the entire length of the base part and in at least a part of the rotating part, and the cooling water supplied through this cooling water supply passage is configured to directly contact the first divided part.

In this way, a cooling water supply passage for cooling the electrode is formed along the entire length of the base section and at least a portion of the rotating section, and the cooling water supplied through this cooling water supply passage is configured to directly contact the first divided body, thereby enhancing the cooling effect of the rotating section, and in particular, by bringing the cooling water into direct contact with the first divided body, the degree of wear on the first divided body can be reduced.

In this case, it is effective to provide a sealing mechanism to prevent water leakage at the spherical mating portion of the swivel joint, and the joining structure of the first and second halves is a tapered fitting or screw type joint.
In other words, since the cooling water supplied through the cooling water supply passage inevitably leaks out through the spherical fitting of the swivel joint and the joining surfaces of the first and second halves, a sealing mechanism can be provided at the spherical fitting to prevent leakage from the grooves at the spherical fitting. Also, if the joining structure of the first and second halves is a tapered fitting, water leakage from the fitting can be prevented.
When the first and second halves are joined by a screw type joint, if the screw part is a straight screw, it is necessary to provide an O-ring or the like as a sealing mechanism around the screw part. However, by making the screw part a tapered screw, the male screw thread and the female screw thread groove are brought into close contact with each other, preventing water leakage from the joint.

In addition, a flange portion is formed on the tip side of the base portion to regulate the rotation angle of the rotating portion, and when the rotating portion rotates to a certain angle, a part of the rotating portion abuts against the flange portion, preventing it from rotating any further. This prevents the rotating portion from rotating too much during dressing work due to wear or other reasons on the tip of the electrode, leading to defects such as poor welding.

In a swivel-type welding electrode in which a rotating part is joined to a base part via a swivel joint and the rotating part is divided along the axial direction into a first divided part at the tip side and a second divided part at the base side, a cooling water supply passage for cooling the electrode is formed along the entire length of the base part and at least a part of the rotating part, and the cooling water supplied through this cooling water supply passage is configured to directly contact the first divided part, thereby improving the cooling effect of the rotating part, preventing wear due to thermal damage, and improving durability. In this case, if a sealing mechanism for preventing water leakage is provided in the spherical fitting part of the swivel joint, water leakage from the fitting part can be prevented. In addition, by using a tapered fitting or screw-type connection for the connection structure of the first and second divided parts, attachment and detachment can be easily performed, and in particular, if a tapered fitting or tapered screw structure is used, a sealing mechanism such as an O-ring is not required for the tapered fitting part. In addition, by providing a flange on the tip of the base and restricting the rotation angle of the rotating part to a certain value or less, problems such as the rotating part rotating too much when dressing the tip of the electrode can be prevented, preventing poor welding, etc.

FIG. 1 is an explanatory diagram for explaining an overview of spot welding. 1A is an explanatory diagram of a welding electrode according to the present invention, in which FIG. 1A shows a state in which a second divided body of a rotating portion has been removed, and FIG. 1B shows a state in which the second divided body has been joined. 1A shows the components of a welding electrode according to the present invention, and FIG. 1B is a cross-sectional view showing the state before the first division, the second division, and the base portion of the rotating portion are assembled, and FIG. 1B is a cross-sectional view showing the state after the second division and the base portion are joined together and the first division is separated. 11A and 11B are explanatory diagrams illustrating a case in which the connecting structure between the first and second divided bodies of the rotating part is a screw type, where (a) is an explanatory diagram illustrating a case in which a straight screw and an O-ring are combined, and (b) is an explanatory diagram illustrating a case in which a tapered screw is used. 13 is an explanatory diagram showing another example of the structure of the first divided body and the second divided body of the rotating portion. FIG. 10A and 10B are explanatory views for forming a flange portion on the tip side of the base portion, where FIG. 10A is a front view and FIG. 10B is an explanatory view for restricting the rotation of a rotating portion. 1A and 1B are explanatory diagrams showing an example of a conventional cooling structure, in which FIG.

The welding electrode according to the present invention is characterized in that in spot welding using a swivel-type electrode in which a rotating part at the tip side is rotatably connected to a base part at the base end via a swivel joint, it is possible to enhance the cooling effect on the rotating part at the tip side of the electrode, which is particularly susceptible to heat generation and wear, and to further improve durability, and that a cooling water supply passage extending from the inside of the base part to the inside of the rotating part is formed up to a part of the rotating part.

Here, an overview of spot welding will be given. Spot welding is a technique in which, as shown in FIG. 1, two materials to be joined _W1 and _W2 are sandwiched between a pair of electrodes D and pressure is applied while an electric current is passed through them, generating resistance heat at the contact surface of the materials to be welded _W1 and _W2 , thereby melting the contact surfaces of the materials to be welded together, and welding them. This technique is often used for welding automobile bodies, etc., but when the contact surfaces of the materials to be welded have a complex shape, a so-called swivel electrode 51 as shown in FIG. 7 may be used.

As shown in FIG. 7, this electrode 51 is integrally equipped with a base portion 52 that is attached to the side of a device such as a stationary welding machine, and a rotating portion 53 that is connected to the base portion 52 by a spherical fitting portion k via a swivel joint 54, and the rotating portion 53 is freely rotatable within a predetermined angle range with respect to the axial direction of the base portion 52.

For this reason, even if the surface of the material to be welded that is sandwiched has a complex shape, when pressure is applied with the electrode 51, the rotating part 53 rotates to follow the surface of the material to be welded, ensuring a sufficient contact area between the material to be welded and the electrode 51, and the amount of current flow is also ensured, preventing poor welding, etc. However, with this type of electrode structure, when the electrode needs to be replaced due to wear, etc., the entire electrode 51 must be replaced, which is costly.

In the conventional swivel electrode 51 shown in FIG. 7, the rotating part 53 is divided into a first division 53a and a second division 53b along the axial direction, and even if the first division 53a, which is particularly subject to severe wear, needs to be replaced, the second division 53b can still be used, and only the first division 53a can be replaced. However, in this case, the cooling water passage s is only provided inside the base part 52, and no cooling water passage is formed in the rotating part 53, which is particularly subject to severe wear. As a result, the cooling effect on the first division 53a, which comes into direct contact with the work and generates heat, is insufficient, and there are problems with the durability of the first division 53a, as described above.

The swivel-type welding electrode 1 according to the present invention is characterized in that the cooling water passage s formed inside the base portion 52 extends to a portion inside the rotating portion 53, thereby enhancing the cooling effect of the first divided body 53a, which is particularly susceptible to thermal damage, etc.

Now, the configuration of the swivel type welding electrode 1 according to the present invention will be described below in order of the base portion 2, the rotating portion 3, the first divided body 3a, the second divided body 3b, the swivel joint 4, etc.
3, the base portion 2 is provided with a spherical portion 2q on the tip side, and a cooling water supply passage s along the axial direction in the center of the inside. In this embodiment, the outer periphery on the base end side of the base portion 2 is a tapered surface 2t for insertion into a tapered hole of the attachment portion on the device main body side, but if the attachment portion on the device main body side is a screw hole, a male screw may be used instead of the tapered surface 2t.
The rotating portion 3 is divided into a first divided body 3a on the tip side and a second divided body 3b on the base side, and a spherical recess 3q is formed on the base side of the second divided body 3b, and a cooling water supply passage s is formed along the axial direction toward the tip side. Also, a tapered protrusion 3t is formed on the outside of the tip side of the second divided body 3b.
Furthermore, a tapered recess 3u capable of being fitted onto the tapered protrusion 3t of the second division 3b is formed on the base end side of the first division 3a.

In the swivel-type welding electrode 1 as described above, the spherical portion 2q of the base portion 2 and the spherical recess 3q of the second division 3b are integrated in a fitted state, and as shown in FIG. 3(b), after an O-ring r is interposed near the peripheral end, the peripheral portion of the spherical recess 3q is crimped with a crimping tool to integrate them.
A swivel joint 4 is formed by the spherical engagement between the spherical portion 2q and the spherical recess 3q, and an O-ring r interposed between the spherical portion 2q and the spherical recess 3q provides a sealing mechanism that blocks the flow of water through the spherical engagement portion k.

In this state, the second divided body 3b can rotate freely within a predetermined angle range in the axial direction of the base body 2, and the tapered recess 3u of the first divided body 3a can be tapered into the tapered protrusion 3t of the second divided body 3b.

When the second divided body 3b is assembled to the base portion 2 as described above, the state shown in Figure 3(b) is obtained, in which the second divided body 3b can be rotated at any angle relative to the base portion 2, and the O-ring r prevents the cooling water supplied through the cooling water supply passage s from leaking to the outside through the spherical fitting portion k of the swivel joint 4.
In addition, the connection between the first and second divisions 3a, 3b is such that the tapered recess 3u of the first division 3a fits taper-wise into the tapered protrusion 3t of the second division 3b, so that the fitting portions of the first and second divisions 3a, 3b are tightly fitted together, thereby preventing cooling water from leaking from the same portion.

In the above embodiment, the first divided body 3a and the second divided body 3b are connected by a taper type fitting, but as shown in Figure 4, it is also possible to use a screw type connection between the male thread 3n of the second divided body 3b and the female thread 3m of the first divided body 3a. However, in this case, if the threaded portion is straight, there is a risk that the cooling water will leak to the outside through the threaded portion, so it is necessary to provide a sealing mechanism such as an O-ring r near the threaded fitting portion. This makes it possible to prevent the cooling water from leaking to the outside. The position of the O-ring r can be arbitrary as long as it is near the threaded portion.
On the other hand, as shown in Fig. 4(b), by making the male thread 3n of the second divided body 3b and the female thread 3m of the first divided body 3a into tapered threads, the thread ridge of the male thread 3n and the thread groove of the female thread 3m come into close contact with each other, making it possible to prevent water leakage without using an O-ring r, etc. In this case, the inclination direction of the taper is such that the male thread 3n tapers toward the tip, and the female thread 3m narrows in diameter toward the deeper side.

The embodiment in FIG. 5 is an example of a case where the division shapes of the first division 3a and the second division 3b are different. In this case, the first division 3a has a T-shaped cross section, and the mating protrusion a on the lower end side can be inserted into the mating recess b of the second division 3b to connect them, and a hole v is provided in the lower surface at the center of the mating protrusion a through which cooling water can enter, improving the cooling effect on the first division 3a.

Next, an embodiment for restricting the rotation angle of the rotating portion 3 will be described with reference to FIG.
In this embodiment, a flange portion 2f is formed on the tip side of the base end portion 2, and the relationship between the distance m between the tip side surface of this flange portion 2f and the base side surface of the second divided body 3b of the rotating portion 3 and the diameter φ of the flange portion 2f is appropriately adjusted, so that when the rotating portion 3 rotates, the lower peripheral end portion E of the second divided body 3b abuts against the flange portion 2f, thereby regulating the rotation angle θ of the rotating portion 3. This is because welding defects are likely to occur if the rotating portion 3 rotates beyond the specified angle θ.

In addition, in this embodiment, the base portion 2, the first divided body 31a, and the second divided body 31b are made of a combination of any of the following materials to enhance the cooling effect: chrome copper, zirconium chrome copper, zirconium copper, beryllium copper, silicon-containing zirconium chrome copper, and brass.

The present invention is not limited to the above-mentioned embodiments. Anything that has substantially the same configuration as the matters described in the claims of the present invention and achieves the same effects falls within the technical scope of the present invention.

In industries where swivel-type welding electrodes with separate rotating parts are widely used, this allows for effective cooling of the rotating parts in particular, and significantly improves durability, so it is expected that this technology will become more widely used in the future.

1...swivel-type welding electrode, 2...base portion, 2f...flange portion, 3...rotating portion, 3a...first divided body, 3b...second divided body, 4...swivel joint, r...O-ring.

Claims (2)

a swivel-type welding electrode in which a rotating part on a tip side is joined to a base part on a base end side via a swivel joint having a spherical fitting part, the rotating part is divided along the axial direction into a first divided body on the tip side and a second divided body on the base end side, and these first and second divided bodies can be joined via any joining structure, and the base part and the second divided body are joined together via a swivel joint, wherein a cooling water supply passage for cooling the electrode is formed in the entire length of the base part and in at least a part of the rotating part, and cooling water supplied through this cooling water supply passage is configured to directly contact the first divided body , the shape of the periphery of the spherical recess of the second divided body constituting the rotating part is made into a hook-shaped cross section that embraces a sealing mechanism, and the sealing mechanism and the second divided body are integrated by crimping the periphery of the spherical recess inward in the radial direction with a seal ring mechanism interposed therebetween . 2. The swivel-type welding electrode according to claim 1 , wherein the first and second divisions are joined by a screw type connection, and a sealing mechanism that comes into contact with the underside of the first division is provided on an end face of the second division that is radially inward from the screw portion engraved on the second division .

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