JPH081353A - Electrode for projection welding or the like - Google Patents

Abstract

PURPOSE:To certainly detect that a part rightly is advanced in receiving hole by placing a magnet at the bottom of part receiving hole and detecting electrical continuity for part detection with a part attracted to a magnet. CONSTITUTION:A part 2 is of a projection bolt, consisting of a shaft part 3, flange part 4 and projection 5 for welding. A magnet 15 is housed in a housing 14 to be fixed. When the shaft part 3 is inserted in a receiving hole 18 from a through hole 19 and then a feed rod 29 is returned in the direction of a narrow line 28, a bolt 3 is attracted by the magnet 15, its tip part is strongly attracted to a guide pin 16. By this attraction, electrical continuity route among a electric wire 23, washer 21, coil spring 22, housing 14 (magnet 15). guide pin 16, bolt 2, inner surface of through hole 19 and main body 6 is made up. By this electrical continuity, presence of the bolt 2 in the receiving hole 18 is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode for projection welding or the like, and is used in a field in which a shaft-shaped part is inserted into a receiving hole of an electrode for welding.

[0002]

2. Description of the Related Art There are various methods for electrically detecting a shaft-shaped component such as a projection bolt which has been inserted into a receiving hole of an electrode and confirming that the component is normally present therein. Although a method is known, conventionally, the receiving holes arranged in the up-down direction are opened upward, and the bolts are inserted there by dropping them by their own weight, and the metal contact between the bolts and the inner surface of the receiving hole. The presence of the parts was confirmed by generating an electric signal by the electric conduction by the.

[0003]

With the above-mentioned prior art, since the parts enter the receiving hole only by self-weight drop, the parts do not enter the normal position and the electrical continuity is maintained. Since it is attempted to obtain it, the conduction may become unstable and a detection error may occur. Further, if the receiving hole is opened in the horizontal direction or downward, there is a problem that the parts do not fully enter or cannot enter.

[0004]

Means for Solving the Problem and Its Action The present invention is provided to solve the above-mentioned problems.
According to a first aspect of the present invention, a magnet is disposed deep inside the receiving hole of the component, and the component is attracted by the magnet and comes into contact with the magnet to establish electrical conduction for component detection. The component that has entered the receiving hole is fully inserted into the receiving hole due to the attractive force of the magnet, and the tip of the component comes into close contact with the magnet, and this close contact allows conduction of the detection current. According to a second aspect, in the first aspect, a guide tube made of an insulating material is installed in a metal body having a cylindrical shape,
Forming a receiving hole while arranging a magnet inside thereof, an end cover made of metal is fixed to an end portion of the main body, and a through hole corresponding to the receiving hole is opened in the end cover, The detection current is characterized by flowing at least through the magnet, the component, the end cover, and the main body. The tip of the component is in close contact with the magnet,
This causes the detected current to flow through the magnet, the part, the end cap and the body to verify that the part is in the receiving hole.

[0005]

1 to 3, the electrode 1 is for projection welding, the component 2 is a projection bolt, and the shaft portion 3 and the flange portion 4 are shown. And a projection 5 for welding. The main body 6 is made of a copper alloy, the welding side member 7 and the fixed side member 8 are integrated by a screw portion 9, and a copper alloy end cover 10 is integrated by a screw portion 11 at the tip of the welding side baffle 7. Has been converted. As is apparent from FIG. 2, the main body 7 has a circular cross-sectional shape, and a guide tube 12 made of a cylindrical insulating material is inserted into the main body 7 and integrated by a fixing pin 13. A magnet (permanent magnet) 15 is housed in the container 14,
A guide pin 16 made of iron is fixed in a state of being in close contact with the magnet 15. The guide cylinder 12 is suitable to be made of Teflon resin, and the internal through holes have a large diameter portion 17 and a small diameter portion 18.
The magnet container 14 is housed in the large-diameter portion 17, and the guide pin 16 enters the small-diameter portion 18. The small-diameter portion 18 forms a receiving hole (hereinafter, referred to as such) for the shaft portion 3, and the through hole 19 opened in the end cover 10 is aligned with the receiving hole 18. The inner diameter of the through hole 19 is set to be slightly larger than the outer diameter of the shaft portion 3, and the dimensions are set so that the shaft portion 3 contacts the inner surface of the through hole 19.

An insulating cup 20 made of an insulating material (for example, Teflon) is fitted inside the fixed-side member 8, and a washer 21 for conduction is fixed to the inner part of the cup, and between the container 14 and the washer 21. The coil spring 22 is inserted, and the elasticity of the coil spring 22 presses the container 14 downward.
An electric wire 23 is connected to the washer 21 and is guided to the outside through the inside of the insulating pipe 24. The other electric wire 25 is connected to the main body 6 (the fixed-side member 8 in the illustrated case).

There are various methods for supplying the bolt 2 to the receiving hole 18, but here, arrows 26, 27, 2 are used.
Supply rod 29 with square motion like 8
As an example. That is, the end of the supply rod 29 is formed with a recess 30 that is opened toward the tip side, and the flange 4 is received therein. A magnet 31 is embedded in the bottom of the recess 30 to hold the bolt 2. ing.

The operation of the above embodiment will be described below.
Shaft part 3 by square motion of supply rod 29
Is inserted into the receiving hole 18 through the through hole 19 and the supply rod 2
When 9 is returned in the direction of arrow 28, bolt 3 moves to magnet 15
Is sucked, and its tip is strongly attracted to the guide pin 16. By this adsorption, the electric wire 23, the washer 21, the coil spring 22, the container 14 (magnet 15), the guide pin 16, the bolt 2, the inner surface of the through hole 19 and the energization path of the main body 6 are established, and such energization is performed. By
The presence of the bolt 2 in the receiving hole 18 is detected. If the bolt 2 does not exist in the receiving hole 18 or if it does not normally enter into the inner part of the receiving hole 18, the bolt 2 and the guide pin 16 cannot be electrically contacted. The current-carrying path is not formed, so that the detection signal of the presence of the component is not issued.
The fact that this detection signal is not output is used as a trigger to prevent the stroke operation of the electrodes. When the flange 4 is pressed against the other member, for example, a steel plate component while the bolt 2 is attracted to the guide pin 16, the coil spring 22 is compressed and the magnet 15 (container 14) retracts in the large diameter portion 17, whereby the flange 4 is the end cover 1
The surface of No. 0 is in close contact with the surface of No. 0, and then the welding current is continuously applied to weld the projection 5 to the counterpart member.

When the outer diameter of the shaft portion 3 is much smaller than the inner diameter of the through hole 19, contact may not occur in this portion. In such a case, the guide pin 16
By making the end face of sloping as shown in FIG. 4, the shaft portion 3 is inclined and the above-mentioned contact is surely caused.

The magnet 15 is housed in the container 14 for the purpose of preventing wear of the magnet 15 and for the guide pin 16 for minimizing welding heat transfer to the magnet. Therefore, the container 14 and the guide pin 16 are not essential to the present invention.

[0011]

[Effects] According to the present invention, since the parts are assisted by the attraction force of the magnet to enter the receiving hole and stop at the normal position, the contact between the magnet and the parts is made strong, which ensures the reliability. Energization is achieved. Therefore, reliable conduction of the detection current can always be obtained. Furthermore, since the component is inserted into the receiving hole up to a predetermined correct position, the component is always held stably regardless of the orientation of the electrode.

[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 plan view of a supply rod.

FIG. 4 is a partial vertical sectional side view showing a modified example of the guide pin.

[Explanation of symbols]

 2 parts 18 receiving hole 15 magnet 6 main body 12 guide tube 10 end cover 19 through hole

Claims (2)

[Claims] 1. Projection welding, characterized in that a magnet is arranged deep in the receiving hole of the component, and the component is electrically attracted to and comes into contact with the magnet to establish electrical conduction for component detection. Etc. electrodes. 2. A guide cylinder made of an insulating material is installed in a metal main body having a cylindrical shape, a magnet is arranged inside the guide cylinder, and a receiving hole is formed therein, and an end of the main body is formed. An end cover made of metal is fixed to the portion, a through hole corresponding to the receiving hole is opened in the end cover, and the detection current flows at least through the magnet, the component, the end cover and the main body. Electrodes for projection welding, etc.