JP2903149B2 - Projection welding electrode with guide pin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding electrode of the type in which a guide pin is inserted into a guide hole of an electrode so as to be able to advance and retreat, and when this guide pin is pushed in, air is ejected from a gap between the guide hole and the guide pin. Things.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIGS. 8 to 11. A guide hole 2 of an electrode 1 is constituted by a small diameter hole 3, a large diameter hole 4, and a medium diameter hole 5 formed therebetween. . On the other hand, the guide pin 6 is provided with the holes 3 and 5 described above.
Small diameter portion 7, middle diameter portion 8, and large diameter portion 9 corresponding to
The small-diameter portion 7 is provided with a required gap 10 between the small-diameter portion 3 and the small-diameter hole 3. The middle diameter portion 8 has a short length when viewed in the axial direction, but is slidably fitted in the middle diameter hole 5, and the large diameter portion 9 is also slidable in the large diameter hole 4. It is stuck in. The members described above are all circular in cross section. The small diameter portion 7 is made of metal, for example, using stainless steel, and a bolt 11 is integrally provided at an end portion thereof. The middle diameter portion 8 and the large diameter portion 9 are made of synthetic resin and are made of, for example, Teflon (trade name). The small-diameter portion 7 is inserted into a portion made of a synthetic resin.
And the part made of synthetic resin are integrated. The large-diameter portion 9 is provided with an air passage 13, which is formed by the cut-out flat portion 13 in FIG. In addition, the electrode 1 has a cap 15 integrated with a main body 14 with a screw portion 16.

Since the end face 17 of the large diameter portion 9 is in close contact with the inner end face 18 of the cap 15, compressed air, which will be described later, is blocked, and the tension of the compression coil spring 19 installed in the large diameter hole 4 is used. The above adhesion is achieved. At the end of the large-diameter hole 4, an inlet 20 for compressed air is opened, and an air pipe 21 is connected to the inlet 20.

[0004] A steel plate part 23 as a mating member is placed on the end face 22 of the electrode 1 and a positioning hole 24 formed in the part is formed.
Through the small diameter portion 7. The small diameter portion 7 is formed with a support portion 25 whose diameter gradually decreases toward the tip. Here, the components are a projection nut indicated by reference numeral 26, 27 is a screw hole, and 28 is a projection for welding. The corners of the screw holes 27 are hooked in the middle of the support portion 25 and are supported as shown in FIG. In the case of this conventional example, the electrode 1 is a fixed electrode, and the electrode 2 is
9 is a movable electrode, which has a receiving hole 30
Has opened. Note that the expression “successfully” used in the above description means a fitting relationship in which slidable and breathable but substantially no diametrical play is present.

[0005] The operation of the above will now be described. When the electrode 29 advances, the nut 26 is pushed down.
At the same time, the entire guide pin 6 is pushed down, and the end face 17
Is separated from the inner end face 18 and the medium diameter portion 8 escapes from the medium diameter hole 5, the compressed air flows from the air passage 13 through the medium diameter hole 5, the gap 10, and the positioning hole 24 to the nut 26 and the steel plate part 23. Flow in between. When the state shown in FIG. 10 is obtained through such a process, a current is applied between the electrodes, and the welding protrusion 2 is formed.
8 melts to complete the welding.

[0006]

In recent years, the accuracy of the position of nut welding is set to be extremely narrow in the gap between the small-diameter portion 7 and the positioning hole 24, for example, in order to assemble the vehicle body with high accuracy. I have. As an example of the dimensions, the inner diameter of the positioning hole 24 is 7.2 mm, the diameter of the small diameter portion 7 is 6.8 mm, and the clearance allowed for air passage is 0.2 mm on the left and right in FIG. Immediately before the welding projection 28 is pressed against the steel plate part 23 as shown in FIG. 10 under such dimensions, since the welding projection 28 is not melted, the lower surface of the nut 26 and the upper surface of the steel plate part 23 are not shown. As is clear from FIG. 10, there are gaps.
Therefore, the airflow caused by the guide pin 6 being pushed down flows out from the positioning hole 24 through the gap below the nut. However, since the inner diameter of the positioning hole 24 is significantly reduced as described above, the flow path resistance at this location is increased, the air pressure in the gap 10 is increased, and finally, the steel plate part 23 is removed from the end face 22 of the electrode. , The air flows in a larger amount toward the gap between the end face 22 and the steel plate part 23 than the gap between the small-diameter portion 7 and the positioning hole 24, and at this time, granular spatter or sand particles are generated. It may be caught between the end face 22 and the steel plate part 23. When the electrode 29 is pressurized and energized in this state, the aforementioned foreign matter 31 bites into the electrode end face 22 as shown in FIG. It comes into contact with the steel plate component 23, and there is a gap as shown in the drawing except for the contact portion, so that current cannot be supplied. Since power is supplied to such a state, the current density at that point is high because the contact area is small, rather close to a point contact, and the welding projection 28 does not melt or is incomplete. Even if it is melted, the raised part 3 was rapidly melted and melted.
2 scatters. It should be noted that the raised portion 32 is
This occurs on the side because the electrode material is made of a relatively soft material such as chromium copper. The reason why the spatter or the like enters the gap 10 is that, when the projection 28 is melted and the lower surface of the nut 26 comes into close contact with the surface of the steel plate part, the outflow destination of the air is blocked, so that the air flow is stopped. Since the spatter scatters right and left from the portion of the projection 28, the spatter enters through a small gap between the positioning hole 24 and the small diameter portion 7. The foreign matter such as spatters entering the gap 10 in this way enters between the end face 22 and the steel plate part 23 when the air flow is restarted.

[0007]

[Means for Solving the Problems and Their Functions] The present invention has been provided to solve the problems described above.
According to a first aspect of the present invention, a guide pin which is inserted into a guide hole of an electrode and comprises a large-diameter portion sliding in the guide hole and a small-diameter portion protruding from the electrode to position a counterpart component. In the type in which air is ejected from the outer peripheral portion of the guide pin when the pin is pushed in, the guide hole through which the small diameter portion penetrates is constituted by a large diameter hole and a small diameter hole,
An exhaust passage communicating between the large-diameter hole and the outside of the electrode is formed in the electrode, and foreign matters such as spatters entering the large-diameter hole are removed by an airflow from the small-diameter hole toward the exhaust passage. It is discharged outside the electrode. Claim 2 provides an annular receiving surface according to claim 1 by an inner diameter difference between the large-diameter hole and the small-diameter hole, and opens an exhaust passage near the receiving surface.
Foreign matter such as spatter that has entered the large-diameter hole collides with the receiving surface, and foreign matter is discharged to the outside of the electrode by airflow from the small-diameter hole to the exhaust passage. Is stopped at the receiving surface, and is discharged out of the electrode by the airflow from the small diameter hole toward the exhaust passage. According to a third aspect of the present invention, in the first aspect, the guide pin has a large diameter portion that slides in the guide hole, and the small diameter portion has an extremely small sliding gap in the small diameter hole. The guide pin has a two-point support configuration, so that even if any force acts on the guide pin in the diameter direction of the pin, the guide pin can easily tilt or Without doing it, it reliably fulfills the centering function. According to a fourth aspect, in the third aspect, the guide pin has a small-diameter portion made of metal and a large-diameter portion made of synthetic resin, and the small-diameter hole through which the small-diameter portion passes is formed in a member made of synthetic resin. Since both of the above-mentioned two-point support locations are sliding of synthetic resin, smooth sliding with metal can be obtained. A fifth aspect of the present invention is a device comprising: a large-diameter portion in which a retractable guide pin inserted into a guide hole of an electrode slides in the guide hole;
The guide hole through which the small diameter portion penetrates is constituted by a large diameter hole and a small diameter hole, and an annular receiving surface is provided by an inner diameter difference between the large diameter hole and the small diameter hole. The foreign matter held on the receiving surface is caused to flow back toward the large-diameter hole by the airflow from the small-diameter hole.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the illustrated embodiments. Members that perform the same functions as the members described in the related art are denoted by the same reference numerals, and detailed description is omitted. Further, in the prior art of FIG. 8, the medium diameter hole 5 and the medium diameter portion 8 are adopted, but here, the one without this part is illustrated. First, referring to the embodiment of FIGS. 1 to 3, FIG. 1 shows that the nut welding has just been completed and therefore
The end face 17 is separated from the inner end face 18 so that air can flow therethrough, and the lower surface of the nut 26 is
3 and the support portion 25 has a screw hole 27
Since it is fitted inside, the air cannot flow out of the positioning hole 24 to the outside. FIG. 3 shows a state in which the end face 17 is in close contact with the inner end face 18 to stop the flow of air.

The guide hole 2 where the small diameter portion 7 penetrates
Is composed of a large-diameter hole 33 and a small-diameter hole 34,
The receiving surface 35 is formed with the inner diameter difference of 4. Large diameter hole 33
An exhaust passage 36 that communicates with the outside of the electrode is provided in the electrode in the diameter direction. The exhaust passage 36 is opened near the receiving surface 35 in order to positively discharge foreign substances that are to stay on the receiving surface 35, and is formed as a diametric hole in the electrode as shown in the figure. I have. Small diameter hole 34
Is opened on a support plate 37 made of a synthetic resin such as Teflon (trade name).
It is press-fitted inside as shown in FIG. When the dimensions of each part in FIG. 3 are exemplified, the diameter of the small diameter portion 7 is 6.8 mm, the inside diameter of the positioning hole is 7.4 mm, the inside diameter of the large diameter hole 33 is 8.5 mm, and the inside diameter of the small diameter hole 34 is 7.0 mm. Receiving surface 3
The width of 5 is 0.75 mm. The sliding gap of the small-diameter hole 34 is 0.1 mm on the left and right sides in FIG. 3, and such a value is a state where there is almost no diametrical play. Part and large diameter part 9
Are substantially supported at two points. This is because when the guide pin 6 is depressed, the two-point support effectively acts on the centering and inclination of the entire pin. The small diameter portion 7 is made of metal, for example, stainless steel, and the large diameter portion 9 is made of a synthetic resin such as Teflon (trade name).

The operation of the above-described embodiment will be described. In the transitional period in which the projection 28 is melted and the nut 26 is pressed against the steel plate part 23, spatters are scattered inward and outward, and a part of the sputter is positioned. At this time, the high-speed air flow is formed from the minute gap between the small-diameter portion 7 and the small-diameter hole 34, so that the spatter does not enter this gap and collide.
At this time, since air cannot flow out of the positioning hole 24, an airflow from the small diameter hole 34 to the exhaust passage 36 is positively formed. Therefore, foreign matter such as spatter is discharged from the exhaust passage 36 to the outside of the electrode immediately upon collision with the receiving surface 35.

In the embodiment shown in FIG. 4, the target component is a projection bolt 38, which comprises a shaft 39, a flange 40, and a welding projection 41. The small diameter portion 7 of the guide pin 6 is formed in a hollow pipe shape, and a shaft portion 39 is provided therein.
Is inserted. Other configurations and operations are the same as those of the previous embodiment.

5 and 6 differ from each other in the form of the exhaust passage, in which a diametrical groove 42 is formed on the end face 22 of the electrode, and the groove 42 is formed near the receiving surface 35. In order to open, the support plate 37 is attached to the end face 2 of the cap 15.
It is arranged close to 2. Here, the end face 17 is the same as the previous embodiment, but the inner end face 18 is the cap 15.
Is formed on the lower surface. In this embodiment, the length of the large-diameter hole 33 is shorter than that of the previous one, but the operation is the same as that described above.

In the embodiment shown in FIG.
In this case, the metal part 5 is open.

In the embodiment shown in FIG. 12, foreign matter entering through the positioning hole 24 with the exhaust passage stopped is discharged upward by an air jet from the small-diameter hole 34 in a transition period while the steel plate part 23 is being removed. Things.

[0015]

According to the present invention, a retractable guide pin inserted into a guide hole of an electrode is composed of a large-diameter portion that slides in the guide hole and a small-diameter portion that projects from the electrode and positions a partner component. When the guide pin is pushed in and the guide pin is pushed in, air is ejected from the outer peripheral portion of the guide pin, and the guide hole through which the small diameter portion passes is constituted by a large diameter hole and a small diameter hole. Since the exhaust passage communicating with the outside is formed in the electrode, the air is constantly exhausted from the exhaust passage, so that the air pressure that pushes up the steel plate part becomes a substantially harmless value, and the electrode end face and the steel plate part Are in close contact with each other, and no air flows between them. Therefore, the above-described foreign matter does not intervene between the two, the short-circuiting of the electrode surface described above is eliminated, and it is possible to prevent the electrode end face from being damaged due to sparking or melting. Further, since a sufficient amount of air can be exhausted from the exhaust passage, it is very suitable for radiating welding heat. Since no foreign matter is present between the electrode end surface and the steel plate part, no gap is generated between the two, and therefore, unnecessary air leakage can be prevented. Since the air flow rate may be set to an amount for discharging foreign matter to the exhaust passage, a minimum necessary air amount is sufficient, which is effective for energy saving. Since the guide hole at the portion where the small diameter portion penetrates is constituted by the large diameter hole and the small diameter hole, the air jet from the small diameter hole can be effectively used for removing foreign matter. Since an annular receiving surface is provided by the inner diameter difference between the large-diameter hole and the small-diameter hole, and the exhaust passage is opened near this receiving surface, foreign matter such as spatters that have entered the large-diameter hole is removed from the small-diameter hole. Since there is a high-speed air flow, the air does not enter the small-diameter hole, but rather collides with the receiving surface, and is discharged out of the electrode by the airflow flowing from the small-diameter hole toward the exhaust passage. Therefore, it is possible to completely prevent the occurrence of air leakage without foreign matter intervening in the small-diameter hole or the close contact portion between the end surface of the large-diameter portion and the inner end surface. Since the entire guide pin is supported at two points at the large diameter portion and the small diameter portion with substantially no backlash and no gap, some bending force acts on the support portion of the small diameter portion. However, since the support is highly stable, the guide pin is not inclined or eccentric, and a highly accurate guide function can be performed. The guide pin has a small-diameter portion made of metal and a large-diameter portion made of synthetic resin, and a small-diameter hole through which the small-diameter portion penetrates is made in a synthetic resin member. The sliding parts of the pins can maintain the sliding relationship between the synthetic resin and metal, respectively.
Therefore, even if the sliding gap is minimized, smooth sliding can be maintained, and even if a bending force acts on the guide pin, the synthetic resin portion exerts a buffer effect in the diametrical direction, and stable sliding holding can be obtained. .

Since there is no exhaust passage, the foreign matter that has entered the large-diameter hole is caused to flow back by the air jet by the action of the air jet from the small-diameter hole and the receiving surface, and the foreign matter becomes large-diameter during the transition period when the steel plate part is lifted. It is also possible to discharge from the holes.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal 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 in which main parts of FIG. 1 are enlarged.

FIG. 4 is a longitudinal sectional side view showing another embodiment.

FIG. 5 is a partial vertical sectional side view showing another embodiment.

6 is an external plan view of the embodiment of FIG.

FIG. 7 is a partial vertical sectional side view showing another embodiment.

FIG. 8 is a longitudinal sectional side view of the prior art.

FIG. 9 is a cross-sectional plan view of a large diameter portion.

FIG. 10 is an enlarged longitudinal sectional side view of a main part of FIG. 8;

FIG. 11 is a partial longitudinal side view showing a local state of an electrode end face and a steel plate part.

FIG. 12 is a vertical sectional side view showing another embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrode 2 guide hole 6 guide pin 9 large diameter portion 7 small diameter portion 33 large diameter hole 34 small diameter hole 36 exhaust passage 35 receiving surface 37 support plate

Claims (5)

(57) [Claims] The guide pin includes a large-diameter portion that slides in the guide hole and a small-diameter portion that protrudes from the electrode to position a mating component. When the pin is pushed in, the air is blown out from the outer periphery of the guide pin. The guide hole through which the small diameter portion passes is composed of a large diameter hole and a small diameter hole, and the large diameter hole communicates with the outside of the electrode. A projection welding electrode with a guide pin, characterized in that an exhaust passage is formed in the electrode. 2. The method according to claim 1, wherein an annular receiving surface is provided by an inner diameter difference between the large-diameter hole and the small-diameter hole, an exhaust passage is opened near the receiving surface, and spatters and the like entering the large-diameter hole. A projection welding electrode with a guide pin, wherein foreign matter is caused to collide with a receiving surface, and the foreign matter is discharged to the outside of the electrode by airflow from a small diameter hole to an exhaust passage. 3. The guide pin according to claim 1, wherein the large-diameter portion slides in the guide hole, and the small-diameter portion has an extremely small sliding gap in the small-diameter hole. A projection welding electrode with a guide pin, wherein the guide pin has a form of two-point support. 4. The guide pin according to claim 3, wherein the small-diameter portion is made of metal and the large-diameter portion is made of synthetic resin, and the small-diameter hole through which the small-diameter portion passes is formed in a member made of synthetic resin. A projection welding electrode with a guide pin, which is characterized in that: 5. A device comprising a large-diameter portion in which a retractable guide pin inserted in a guide hole of an electrode slides in the guide hole and a small-diameter portion protruding from the electrode to position a counterpart component. A projection with a guide pin, wherein the guide hole through which the small-diameter portion passes is constituted by a large-diameter hole and a small-diameter hole, and an annular receiving surface is provided by an inner diameter difference between the large-diameter hole and the small-diameter hole. Welding electrode.