JPH09300081A - Electrode for electric resistance welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the air-tightness and to prevent the center deviation of a guide pin by bringing the end surface of guide part of an electrode into close contact with the inner end surface of large diameter part of a guide hole and forming an air passage in the axial direction of a guide pin in the guide part. SOLUTION: In the electrode for electric resistance welding, at the time of pushing down a nut 14 by advancing the movable electrode, the close contact between the end surface 24 of the guide part 8 and the inner end surface 25 of the large diameter hole 4, is released and compressed air is spouted to the outside from the gap 12 through the interval between the end surfaces 24, 25 from an air passage 22 of the guide part 8. In this state, at the time of supplying power by press-contact between the nut 14 and a steel plate parts 13, welding is completed. At this time, the spatter is flown away with the compressed air and does not enter the gap 12. Further, air-cooling is applied to the generated heat at the time of welding. In this operation, since the guide part 8 is firmly fitted into the guide hole 4, the center deviation and the eccentricity are not developed and the gap 12 is uniformly held over the whole periphery and the relative position between the nut 14 and the steel plate parts 13 can accurately be set.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a guide hole having a circular cross section in an electrode, which comprises a small diameter hole and a large diameter hole, and a guide pin which comprises a small diameter portion and a large diameter portion. The large diameter part and the large diameter part are fitted in the small diameter hole and the large diameter hole of the guide hole, respectively, and when the guide pin is pushed down, compressed air is ejected from the gap between the small diameter hole and the small diameter part. The present invention relates to an electrode for welding.

[0002]

2. Description of the Related Art As the prior art most closely related to the present invention, Japanese Utility Model Publication No. 54-9849 and Japanese Utility Model Publication No. 62-327.
Publication No. 14 is cited. The former is shown in FIG. 8 and the latter is shown in FIG. First, referring to FIG. 8, the guide hole 2 in the electrode 1 is composed of a small diameter hole 3 and a large diameter hole 4, and a taper hole 5 is provided at a connecting portion between both holes 3 and 4. on the other hand,
The guide pin 6 is composed of a small diameter portion 7 and a large diameter portion 8, and a taper portion 9 is provided at a connecting portion between both portions 7 and 8. A coil spring 10 is inserted into the guide hole 2 and its elasticity acts in a direction to push up the guide pin 6, and a vent 11 for introducing compressed air is opened in the electrode 1.
As shown, the tapered portion 9 is in close contact with the tapered hole 5 due to the elasticity of the coil spring 10. A gap 12 is provided between the small diameter hole 3 and the small diameter portion 7. The steel plate component 13 is positioned on the electrode 1 by receiving the guide pin 6 therethrough, and the conical portion 15 is inserted into the screw hole of the projection nut 14 to advance the movable electrode (not shown). I have it. The electrode 1 has a body 16 and a cap 17 integrated with a screw portion 18.
The outer shape and the guide hole 2 have a circular cross section.

The operation of the one shown in FIG. 8 will be described. When the movable electrode advances, its end face abuts against the end of the guide pin 6 and is pushed down, so that the tapered portion 9 separates from the tapered hole 5, so that the compression from the vent hole 11 is performed. Air is ejected from the gap 12 to the outside through the gap in the tapered portion.
Then, when the movable electrode further advances, the projection nut 14 is pressure-bonded to the steel plate component 13, and when a welding current is subsequently applied, the nut 14 is welded to the steel plate component 13. In the transitional period in which the welding is performed, spatters are scattered. However, the spatters are eliminated by the air ejected from the gap 12, and are prevented from entering the gap 12. In addition, it is cooled by the jet air.

Next, the conventional technique shown in FIG. 9 will be described. Members having the same functions as those shown in FIG. 8 are designated by the same reference numerals as those in FIG. 8 and detailed description thereof is omitted.
At the boundary between the large-diameter portion 8 and the small-diameter portion 7, an end surface 19 formed of a diametrical annular flat surface is formed, while at the boundary between the large-diameter hole 4 and the small-diameter hole 3, the large-diameter hole 4 is formed. An inner end surface 20 is formed, and an O-ring 21 for maintaining airtightness is fitted in the large diameter portion 8.

The operation of the one shown in FIG. 9 will be described. This is almost the same as the operation of the one shown in FIG. However, the difference is that the compressed air is not ejected from the gap 12 and the compressed air is introduced to push up the guide pin 6, and the O-ring 21 keeps airtightness. Therefore, the scattering of spatter and the cooling action are not performed here.

[0006]

Problems to be Solved by the Invention The above-mentioned conventional technique has the following problems. The problem with FIG. 8 is that when the guide bin 6 is pushed down, the taper portions are released from each other, so that the guide pin 6 is in a so-called floating state, and therefore the guide pin 14 is pressed by the steel plate part 13 before the guide pin 6 is pressed. 6 itself becomes eccentric in the guide hole 2, and the nut 14 moves to the steel plate part 13
May not be welded in the correct position. Further, the adhesion of the taper portion has a problem that the adhesion for obtaining the airtightness cannot be secured unless the taper angle between the taper hole 5 and the taper portion 9 is finished with extremely high accuracy, and the factory air leaks. Would be uneconomical.

The problem with FIG. 9 is that it is impossible to scatter spatter and perform air cooling. Rather, it is a technology that does not consider spattering or air cooling.

[0008]

[Means for Solving Problems and Problems] The present invention is
The present invention is provided to solve the above-mentioned problems. According to claim 1, the guide hole having a circular cross section in the electrode is composed of a small diameter hole and a large diameter hole, and the guide pin has a small diameter portion and a large diameter portion. The small diameter portion and the large diameter portion of the guide pin are fitted in the small diameter hole and the large diameter hole of the guide hole, respectively, and when the guide pin is pushed down, the compressed air is compressed into the small diameter hole and the small diameter portion. In the type that ejects from the gap between the two, the large diameter part of the guide pin is a guide part that fits snugly into the large diameter hole, and the end face of the guide part and the inner end face of the large diameter hole are in close contact. It is characterized in that an air passage is formed in the guide part in the axial direction of the guide pin.The compressed air is completely blocked by the close contact between the end face of the guide part and the inner end face of the large diameter hole. The guide pin is retracted when the movable electrode advances. , The entire guide pins move smoothly without or causing deflection core by the axis setting function of the guide portion. By this retreat, the above-mentioned close contact part separates,
The compressed air is ejected from the air passage through the gap at the small diameter portion. According to claim 2, in claim 1,
By forming a medium-diameter hole between the small-diameter hole and the large-diameter hole of the guide hole, the large-diameter hole is made into at least a two-stage type, and a medium-diameter portion is formed between the small-diameter portion and the large-diameter portion of the guide pin. By doing so, the end face of the guide portion has at least two main end faces and sub end faces.
It is a stepped type, and the inner end surface of the large-diameter hole is characterized in that it is a main inner end surface and a sub inner end surface with which one or both of the main end surface and the sub end surface of the guide part are in close contact. Either or both of the main inner end face or the sub inner end face and the sub inner end face are in close contact with each other to maintain airtightness. Claim 3 is Claim 2
, The middle diameter part of the guide pin fits snugly into the middle diameter hole of the guide hole, and the axial length of this fitting is set shorter than the length that the guide pin retracts during welding. With the above-mentioned fitting, it is possible to prevent the air from flowing even in the middle diameter portion to realize a more airtight state and to retract the guide pin. The medium-diameter portion comes out of the medium-diameter hole to secure an air flow passage, and the shaft center setting function of the guide portion allows the medium-diameter portion to smoothly come in and out. A fourth aspect of the present invention is characterized in that, in the first aspect, the air passage is formed by providing a flat portion on the outer peripheral surface of the guide portion, and the compressed air is ejected through the flat portion. A fifth aspect of the present invention is characterized in that, in the second aspect, the air passage is formed by providing a flat surface portion on the outer peripheral surface of the guide portion, and the compressed air is ejected through the flat surface portion. A sixth aspect of the present invention is characterized in that, in the first aspect, the air passage is formed by providing a groove on the outer peripheral surface of the guide portion, and the compressed air is ejected through the groove. A seventh aspect of the present invention is characterized in that, in the first aspect, the small diameter portion of the guide bin is made of metal, the large diameter portion is made of synthetic resin, and the electrodes are made of metal having good conductivity. Then, the end face of the guide portion is seated on the inner end face of the metal due to the softness of the synthetic resin, the contact familiarity at this close contact portion becomes good, and the airtightness is more reliably maintained.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described with reference to the illustrated examples. First, FIG. 1 and FIG.
However, the same reference numerals are shown in the drawings and the detailed description thereof is omitted for the members having the same functions as the members described in FIGS. 8 and 9. The small diameter part 7 of the guide pin 6 is made of stainless steel, while the large diameter part 8
Is made of synthetic resin, and examples of synthetic resin include Teflon and nylon mixed with glass fiber. There are various methods for integrating the small diameter portion 7 and the large diameter portion 8 such as a screw-in type and a nut tightening type. Here, when the large diameter portion 8 is molded, the small diameter portion 7 is also integrated. The method of casting is adopted. The air passage 22 formed in the axial direction of the guide pin is formed by forming a flat surface portion 23 as is clear from FIG. In addition, cap 1
7 and the main body 16 are made of a metal having good conductivity, for example, a copper alloy.

The large diameter portion 8 fits snugly into the guide hole 2 having a circular cross section. The term "close" means that the large-diameter portion 8 can slide with no substantial gap in the guide hole 2, and in other words, if there is no air passage 22, the compressed air flow is The guide pin 6 can be slid with a very small amount, or can be slid without causing a flow. By doing so, the guide pin 6 as a whole is not slightly tilted, and center runout and eccentricity are prevented. . Such a large diameter portion 8 is used as a guide portion, and the reference numeral 8 is also displayed on the guide portion. End face 24 of guide portion 8
And the inner end surface 25 of the large-diameter hole 4 are in close contact with each other, and both end surfaces are installed in the form of a plane orthogonal to the axis of the guide pin 6. Reference numeral 26 indicates an insulating plate. Further, in the case of the projection nut shown in the drawing, the electrodes generally have a diameter of 25 mm, an overall electrode length of 85 mm, and a guide pin small diameter portion having a diameter of 7 mm.

To explain the operation of this embodiment, in FIG. 1, the guide pin 6 is pushed upward by the air pressure from the vent 11 and the tension of the coil spring 10, and the end face 2
4 is strongly seated on the inner end surface 25 to completely stop the outflow of compressed air. Here, when a movable electrode (not shown) advances and pushes down the nut 14, the surfaces 24 and 25 are separated from each other, so that the compressed air passes through the air passage 22.
To the outside through the gap 12 through the surfaces 24 and 25. In this state, when the nut 14 is pressed against the steel plate component 13 and electricity is applied, welding is completed, and spatters scattered at this time are scattered by compressed air and do not enter the gap 12. . Further, air cooling is performed against heat generated during welding. In the above operation, since the guide portion 8 is fitted in the guide hole 4 properly, the runout and the eccentricity do not occur, and the gap 1
2 can be held uniformly over the entire circumference, air can be jetted uniformly, and the relative position between the nut 14 and the steel plate component 13 can be accurately set.

3 and 4, the medium-diameter hole 27 is formed between the small-diameter hole 3 and the large-diameter hole 4 of the guide hole 2 so that the large-diameter hole becomes a two-stage type. Has become. A medium diameter portion 28 is formed between the small diameter portion 7 and the large diameter portion 8 of the guide bin 6, and the end surface of the guide portion 8 has a main end surface 29 and a sub end surface 30.
It is a two-stage type. The medium-diameter portion is provided as described above to form a two-stage type, but it is also possible to form a three-stage type, and therefore at least a two-stage type.
The inner end surface of the large-diameter hole is also divided into a main inner end surface 31 and a sub inner end surface 32, and the main end surface 29 and the sub end surface 30 of the guide portion 8 are divided.
And are respectively in close contact with either or both of the main inner end surface 31 and the sub inner end surface 32 of the large diameter hole 4.

Then, the middle diameter portion 28 of the guide pin is fitted in the middle diameter hole 27 of the guide hole in a snug state. The axial length L1 of this fitting is set shorter than the length L2 with which the guide pin 6 is retracted during welding. By doing so, the medium diameter portion 28 is pulled out from the medium diameter hole 27 to form the passage 33 as shown in FIG. 4, and when returning to the original state, the centering function of the guide portion 8 allows a smooth fitting. Done.

FIGS. 5 and 6 show another method of installing the air passage 22. In FIG. 5, four concave grooves 34 are formed in the axial direction. 4 has four through holes 35 in the axial direction formed near the outer periphery of the guide portion 8, and each through hole 35 is open to the end surface of the guide portion 8.

In the embodiment shown in FIG. 7, a medium diameter hole 27 and a medium diameter portion 28 are provided.
However, the gap 36 is provided instead of a proper fitting. Therefore, the above L1 and L2
The long and short relationship with is reversed.

[0016]

According to the present invention, the guide portion of the guide pin fits snugly into the large diameter portion of the guide hole, and the end surface of the guide portion and the inner end surface of the large diameter hole are in close contact with each other by the annular flat surfaces.
Unlike the prior art, it is not necessary to process and manufacture the tapered surface with difficulty, and reliable airtightness is maintained. And since the guide part is fitted so that center runout and eccentricity of the guide pin do not occur, the gap at the small diameter part is maintained uniformly over the entire circumference, and the relative position between the projection nut and the steel plate part is also Secured with high precision. Since the stepped structure is adopted for the guide hole and the guide pin is adapted to the stepped structure so as to perform the surface contact as described above, it is very advantageous for maintaining the airtightness. Since the medium-diameter hole and the medium-diameter portion are in a proper fitting relationship, the function of maintaining the airtightness is fulfilled at this fitting portion. Even if a foreign matter is caught in the contact portion of each end surface for some reason, air leakage can be prevented by the airtightness maintaining function of the fitting portion. Further, since the guide portion firmly fulfills the centering function, the medium diameter hole and the medium diameter portion can be smoothly pulled out and entered. Since the large diameter portion of the guide pin is made of synthetic resin, the air passage can be formed by a molding method, which is very advantageous in terms of manufacturing. Further, even when cutting is performed, the workability is good and it is also advantageous. Since the electrode itself is made of metal and the end surface made of synthetic resin is seated on the inner end surface of the large-diameter hole, initial familiarization proceeds on the synthetic resin side, and good airtightness can be obtained. As an effect that can be described from the examples, since each seating surface is in a form orthogonal to the axis of the guide pin, it is possible to obtain a highly accurate product that is easy to process, and is therefore very advantageous for improving airtightness. Is. Since the length of the guide portion is about half of the total length of the guide pin, extremely stable operation is realized for preventing runout and eccentricity.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line (2)-(2) of FIG.

FIG. 3 is a partial longitudinal sectional side view showing another embodiment.

FIG. 4 is a vertical sectional side view in which a part of the embodiment of FIG. 3 is enlarged.

FIG. 5 is a plan view showing a case where a groove is provided in the guide portion.

FIG. 6 is a plan view when a through hole is provided in the guide portion.

FIG. 7 is a partial vertical sectional side view similar to FIG. 4, showing another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrode 2 Guide hole 3 Small diameter hole 4 Large diameter hole 6 Guide pin 7 Small diameter part 8 Large diameter part, guide part 12 Gap 24 End face 25 Inner end face 22 Air passage 27 Medium diameter hole 28 Medium diameter part 29 Main end face 30 Sub end face 31 Main inner end face 32 Sub inner end face 23 Plane portion 34 Recessed groove

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[Procedure amendment]

[Submission date] August 10, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line (2)-(2) of FIG.

FIG. 3 is a partial longitudinal sectional side view showing another embodiment.

FIG. 4 is a vertical sectional side view in which a part of the embodiment of FIG. 3 is enlarged.

FIG. 5 is a plan view showing a case where a groove is provided in the guide portion.

FIG. 6 is a plan view when a through hole is provided in the guide portion.

FIG. 7 is a partial vertical sectional side view similar to FIG. 4, showing another embodiment.

FIG. 8 is a vertical sectional side view showing a conventional technique.

FIG. 9 is a vertical sectional side view showing another conventional technique.

[Explanation of reference numerals] 1 electrode 2 guide hole 3 small diameter hole 4 large diameter hole 6 guide pin 7 small diameter portion 8 large diameter portion, guide portion 12 gap 24 end face 25 inner end face 22 air passage 27 medium diameter hole 28 medium diameter portion 29 main End face 30 Sub end face 31 Main inner end face 32 Sub inner end face 23 Flat surface portion 34 Recessed groove

Claims (7)

[Claims] 1. A guide hole having a circular cross section in an electrode is composed of a small diameter hole and a large diameter hole, and a guide pin is composed of a small diameter portion and a large diameter portion, and the guide pin has a small diameter portion and a large diameter portion. In the type that is fitted into the small diameter hole and the large diameter hole of the guide hole respectively, and when the guide pin is pushed down, compressed air is ejected from the gap between the small diameter hole and the small diameter portion,
The large diameter part of the guide pin is a guide part that fits snugly into the large diameter hole, and the end face of the guide part and the inner end face of the large diameter hole are configured to be in close contact with each other. An electrode for electric resistance welding, characterized in that an air passage is formed in the axial direction. 2. The large-diameter hole according to claim 1, wherein the large-diameter hole has at least two stages by forming a medium-diameter hole between the small-diameter hole and the large-diameter hole of the guide hole, and the small-diameter portion and the large-diameter portion of the guide pin are formed. By forming a medium-diameter portion between the guide portion and the end portion, the end surface of the guide portion has at least two steps of a main end surface and a sub-end surface, and the inner end surface of the large-diameter hole is either the main end surface or the sub-end surface of the guide portion. Alternatively, an electrode for electric resistance welding, characterized in that it has a main inner end surface and a sub inner end surface which are in close contact with each other. 3. The medium diameter portion of the guide pin according to claim 2, wherein the medium diameter portion of the guide pin is fit into the medium diameter hole.
The electrode for electric resistance welding is characterized in that the axial length of this fitting is set shorter than the length by which the guide pin is retracted during welding. 4. The electrode for electric resistance welding according to claim 1, wherein the air passage is formed by providing a flat surface portion on the outer peripheral surface of the guide portion. 5. The electrode for electric resistance welding according to claim 2, wherein the air passage is formed by providing a flat surface portion on an outer peripheral surface of the guide portion. 6. The electrode for electric resistance welding according to claim 1, wherein the air passage is formed by providing a groove on the outer peripheral surface of the guide portion. 7. The electrical equipment according to claim 1, wherein the small diameter portion of the guide pin is made of metal, the large diameter portion is made of synthetic resin, and the electrodes are made of metal having good conductivity. Electrode for resistance welding.