JPH034459Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a shaft connection structure of an electrode holder, and more specifically, to a welding head used in welding operations such as series spot welding and indirect spot welding. The present invention relates to a shaft connection structure for an electrode holder that makes it possible to improve the strength of the shaft that connects the welding head main body and the electrode holder.

[Background of the invention] For example, in series spot welding and indirect spot welding, a large current is applied while mechanically pressurizing the material to be welded with an electrode tip to weld the material to be welded.

Therefore, the structure of a general electrode holder in a welding head used for such welding work was first developed.
An example is shown in the figure. In this case, the electrode holder 2 is connected by a shaft 4 to a welding head body (not shown). A small-diameter connecting portion 8 is formed on the shaft 4 via a stepped portion 6, and an insulating sleeve 1 is attached to this connecting portion 8.
The electrode holder 2 is connected via 0. This electrode holder 2 holds an electrode chip 12.

By the way, when carrying out actual welding work, the electrode tip 1 is attached to the material to be welded (not shown).
A reaction force of the pressing force No. 2 acts on the shaft 4. In particular, when considering the stress distribution at this time, stress is concentrated at the portion where the cross-sectional area changes rapidly, that is, at the step portion 6. Therefore, when welding work is carried out continuously, cracks may occur in the stepped portion 6 of the shaft 4 where stress is concentrated, which may eventually lead to an accident in which the shaft 4 is damaged.

Conventionally, in order to prevent such damage to the shaft 4, sufficient strength has been ensured by increasing the outer diameter of the shaft 4. However, on the other hand, it has been pointed out that there is a disadvantage that the followability of the electrode tip during welding is reduced due to the corresponding increase in weight, resulting in deterioration of welding quality.

[Purpose of the invention] The present invention was made in order to overcome the above-mentioned disadvantages, and the purpose of the present invention is to connect a shaft with a straight shape without a stepped portion to the electrode holder so that both ends of the shaft are connected to the electrode holder in opposite directions. By connecting through a bent locking sleeve, it is ensured that the shaft does not fall out from the sleeve, and stress concentration acting on the shaft is avoided, improving its strength and further reducing the weight of the welding head. It is an object of the present invention to provide a shaft connection structure for an electrode holder that contributes to the present invention.

[Means for achieving the object] In order to achieve the above object, the present invention has a structure in which an electrode holder for holding an electrode is connected to a shaft extending from a welding head body, and has a slot. A sleeve with which the tip of the shaft engages and is bent outward at one end and bent inward at the other end so as to be perpendicular to the axial direction of the shaft, and an insulator that is fitted onto the sleeve or in-molded. The electrode holder is connected and fixed by interposing an insulating sleeve made of a material at the tip of the rod-shaped shaft.

[Embodiment] Next, a preferred embodiment of the shaft connection structure of the electrode holder according to the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 2, reference numeral 30 indicates a welding head with a balance mechanism to which the electrode holder shaft connection structure according to the present invention is applied. This welding head 30 with a balance mechanism basically consists of a main body part 32, an equalizer part 34 for equalizing the pressure applied to the electrodes, and an electrode part 36 having a set of electrodes.

First, a support part 3 is provided at the center of the upper part of the main body part 32 which is connected to a displacement means (not shown) via an arm 37.
8 extends, and the distal end of this support portion 38 is cut out into a bifurcated shape. The equalizer 40 is pivotally supported at the tip of the support portion 38 so as to be swingable. The equalizer 40 is made of a flat plate,
A concave portion 42 having a smooth curved surface is provided at both ends of the lower part.
a, 42b are formed, and these recesses 42a, 42
Rollers 44a, 44b face shafts 46a, 46b.
It is rotatably attached at one end side. In this case, these shafts 46a, 46b are slidably fitted into the main body 32 with their axes parallel to each other.

Next, the electrode section 36 connected to the other end side of the shafts 46a, 46b will be explained. In this case, the shaft 46 can be connected using the connection structure according to the present invention.
The electrode portion 36 is connected to a and 46b. That is, as shown in FIG. 3, the shaft 46a,
46b has a constant diameter and does not have a stepped portion,
The electrode holders 52a and 52b are connected to each other via lock sleeves 48a and 48b interposed at the tips of the straight rods and insulating sleeves 50a and 50b fitted over the lock sleeves 48a and 48b.

As shown in FIG.
Flange portions 53a and 53b bent outward are formed at one end of the 8b, and flange portions 53a and 53b are formed at the other end and are perpendicular to the axial direction of the shafts 46a and 46b in order to lock the tips of the shafts 46a and 46b. Locking portions 54a and 54b are formed by being bent inward in the opposite direction to the flange portions 53a and 53b. In addition, the lock sleeve 48a,
48b has slots 55a and 55 in its axial direction, respectively.
b is formed. The material of the insulating sleeves 50a and 50b is, for example, synthetic resin such as Bakelite. This insulating sleeve 50a,
50b has flange portions 56a, 56b formed at the end, and slots 57a, 57 in the axial direction.
b is formed. According to this embodiment, the insulating sleeves 50a and 50b are constructed separately from the lock sleeves 48a and 48b, but synthetic resin such as Bakelite is in-molded on the outside of the lock sleeves 48a and 48b. Both may be configured integrally.

Next, the electrode holders 52a and 52b are made of a good conductor, and the shafts 46a and 46 on the rear end side are connected to each other.
A hole 58a, into which the shaft 46a, 46b is inserted through the locking sleeve 48a, 48b and the insulating sleeve 50a, 50b, is connected to the hole 58a,
58b and slots 60a, 60b are formed, and the shaft 46 is connected to the slots 60a, 60b.
Lock bolts 62a, 62 for fixing a, 46b
b is screwed in. Moreover, the electrode holders 52a, 52
Similarly, holes 63a, 63b and slots 64a, 64b are formed on the tip side of b, and electrodes 66a, 66b are inserted into the holes 63a, 63b through bolts screwed into the slots 64a, 64b. Retained. Note that reference numerals 68a and 68b are terminals for supplying welding current to the electrodes 66a and 66b from a power source (not shown).

The welding head with a balance mechanism to which the electrode holder shaft connection structure according to the present invention is applied is basically constructed as described above, and its operation and effects will be explained next.

First, by displacing the arm 37 downward, the welding head 30 with a balance mechanism connected to the arm 37 is lowered. The electrode 6 held by the electrode holders 52a and 52b
The tips of 6a and 66b are brought into contact with the material to be welded and pressed with a predetermined pressure. As a result, shaft 46
a, 46b rise slightly, and rollers 44a, 44b
comes into contact with the recesses 42a and 42b. In this case, if the reaction forces of the pressurizing forces transmitted from each of the electrodes 66a and 66b are different, the equalizer 40 swings about its fulcrum to absorb the pressure difference. Therefore, the electrodes 66a and 66b always press the material to be welded with equal pressure. And the electrode 66
By passing a welding current between terminals a and 66b through terminals 68a and 68b, the materials to be welded can be joined under suitable conditions.

Moreover, according to this embodiment, as shown in FIG.
Shaft 46 in the connection part of a and 46b
A lock sleeve 48a interposed between a and 46b,
Flange portions 53a, 5 bent to the outside of 48b
3b and a locking portion 5 bent inwardly.
Since the shafts 4a, 54b are engaged with the tips of the shafts 46a, 46b, they act to prevent the straight shafts 46a, 46b from coming off. Furthermore, when electricity is applied, the current flows only between the welded material and the electrodes 66a, 66b due to the insulating effect of the insulating sleeves 50a, 50b. Furthermore, shafts 46a, 46b
Since it has a straight shape, the electrodes 66a,
While the reaction force generated when the material to be welded is pressurized by the shaft 66b acts on the shafts 46a and 46b, no local stress concentration occurs. Therefore, the shaft 46
The strength of parts a and 46b is relatively improved and can withstand welding work for a long period of time.

[Effects of the invention] As described above, according to the invention, the strength is increased because the straight shaft is connected to the electrode holder by using the lock sleeve having the above structure. At the same time, local stress concentration due to repeated welding work can be avoided, and accidents such as damage to the shaft can be prevented. Furthermore, since the diameter of the shaft can be made relatively smaller by the increase in strength, the weight of the electrode can be reduced. Therefore, the followability of the electrode becomes good during welding, and the quality of welding is improved.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments, and various improvements and design changes can be made without departing from the gist of the present invention. Of course.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view showing a conventional electrode holder and shaft connection structure, FIG. 2 is a perspective explanatory view of a welding head to which the electrode holder shaft connection structure of the present invention is applied, and FIG. 3 4 is an exploded perspective view showing the parts constituting the shaft connection structure.
The figure is a partially sectional explanatory view of the shaft connection structure. 30... Welding head with balance mechanism, 32...
Main body part, 34... Equalizer part, 36... Electrode part, 40... Equalizer, 44a, 44b... Roller, 46a, 46b... Shaft, 48a, 4
8b... Lock sleeve, 50a, 50b... Insulating sleeve, 52a, 52b... Electrode holder, 6
2a, 62b...Rock bolt, 66a, 66b
...Electrode, 68a, 68b...Terminal.

Claims (1)

[Scope of utility model registration request] A structure in which an electrode holder for holding an electrode is connected to a shaft extending from a welding head main body,
A sleeve having a slot, with which the tip of the shaft engages, one end side bent outward and the other end side bent inward so as to be perpendicular to the axial direction of the shaft, and a sleeve fitted externally to the sleeve; A shaft connection structure for an electrode holder, characterized in that the electrode holder is connected and fixed by interposing an insulating sleeve made of an in-molded insulating material at the tip of a rod-shaped shaft.