JPH051111B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a nut welding method for welding a nut to a workpiece to be welded by projection welding, and is particularly suitable for welding a vertical workpiece from a lateral direction. This invention relates to a nut welding method that can prevent nuts from falling off regardless of the situation.

[Conventional technology]

For example, when welding a nut to a side rail (hereinafter referred to as a workpiece) that constitutes the frame of an automobile by projection welding, conventionally the surface of the workpiece 1 to be welded is held approximately horizontal as shown in FIG. A through hole 1a formed in a workpiece 1 is inserted into a positioning pin 3 provided on a fixed electrode 2, a nut 4 is inserted into the upper surface of the hole 1a through the through hole 4a, and the movable electrode 5 applies pressure and electricity. I was doing some welding.

In addition, when welding the nut 4 to the almost vertical surface of the workpiece 1 as shown in FIGS. 3B and C, the workpiece 1 is rotated approximately 90 degrees to make the surface to be welded approximately horizontal, as shown in FIG. 3A. Welding was carried out in such a position.

Note that the proposal for this type of mating device was made by Jitsukai Sho.
A component fitting device disclosed in Japanese Patent No. 59-39133 is known in which a guide pin is butted against the shaft of a workpiece, and a washer is fed to the shaft by an air flow along the guide pin.

[Problem that the invention seeks to solve]

However, according to the above-mentioned conventional nut welding method, welding cannot be performed unless the surface to be welded is substantially horizontal, and therefore there is a problem in that the workpiece 1 must be rotated. Particularly when the workpiece 1 is long and heavy, a large reversing mechanism is required, resulting in an increase in equipment cost.

Furthermore, when there are a large number of nuts 4 to be welded and welding over a wide range in the longitudinal direction, the workpiece 1 must be rotated and moved back and forth in the longitudinal direction repeatedly, resulting in poor workability. It was hot.

The proposal disclosed in the above-mentioned publication is a device for automatically fitting a component onto the shaft of a workpiece, and no consideration was given to projection welding.

In addition, the welding device disclosed in Japanese Utility Model Publication No. 59-114284 uses a nut automatic feeding device to hold a nut on a horizontal workpiece using a nut guide vertically protruding above the lower fixed electrode. The workpiece is equipped with an air blowing device that automatically feeds the workpiece diagonally from above, places it on a horizontal workpiece, and blows air toward the vicinity of the nut guide member. This is a nut blowing device for the purpose of preventing welding.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a nut welding method that can easily weld a nut to a vertical welding surface of a workpiece without rotating the workpiece. do.

[Means for solving problems]

In order to achieve the above object, the present invention attaches the welding surface of the welding member vertically to a positioning pin provided horizontally on a fixed electrode through a through hole formed in the welding surface of the welding member, and then After the nut is horizontally mounted on the small diameter portion of the positioning pin through the through hole of the nut, when performing projection welding by applying pressure and electricity with a movable electrode that moves in the horizontal direction, This is a method in which projection welding is performed by constantly blowing compressed air from diagonally downward onto the nut attached to the positioning pin to prevent it from falling off.

[Effect]

According to the method of the present invention, even if the welding surface of the workpiece is not horizontal but vertical, the nut attached to the positioning pin formed on one electrode is blown with compressed air, so it will not fall off. do not have. Therefore, the nut can be easily held on the positioning pin, and projection welding can be easily performed on the vertical surface of the workpiece from the lateral direction.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the nut welding method according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In the figures, parts that are the same or equivalent to those of the conventional example shown in FIGS. 2 and 3 are designated by the same reference numerals.

Large diameter portion 3a of positioning pin 3 provided on the axis of one end of fixed electrode 2 supported in a substantially horizontal direction
A through hole 1a formed in the workpiece 1 is inserted into the workpiece 1, and the workpiece 1 is positioned and mounted almost perpendicularly to the fixed electrode 2. Next, attach the nut 4 to the small diameter portion 3b of the positioning pin 3.
Position and install. The nut 4 is fed to the positioning pin 3 using a known nut feeder.

A compressed air supply nozzle 6 is provided diagonally below the positioning pin 3, and compressed air supplied from an air source (not shown) is blown onto the nut 4 from this nozzle 6, and the nut 4 is
This prevents the pin from falling off the positioning pin 3. In this state, the movable electrode 5 pressurizes the nut 4 using a cylinder (not shown), and current is applied between the fixed electrode 2 and the movable electrode 5 to perform projection welding of the nut 4 to the workpiece 1.

According to this embodiment, even if the surface of the workpiece 1 to be welded is almost vertical, the nut 4 can be prevented from falling off the positioning pin 3 by blowing compressed air, and the nut 4 can be easily removed. Projection welding to the workpiece 1 can be performed while holding the workpiece.

Furthermore, by appropriately setting the direction of the compressed air supply nozzle 6, it is possible to correct supply defects such as inclination or misalignment of the nut 4. Furthermore, if the nut 4 is not fully inserted into the positioning pin 3, it can be blown away with compressed air to prevent welding defects from occurring.

In the above-mentioned embodiment, the case where the surface of the workpiece 1 to be welded is almost vertical is explained, but the mounting posture of the workpiece 1 to the fixed electrode 2 does not have to be vertical, for example, it may be inclined with respect to the vertical surface. It's okay.

〔Effect of the invention〕

As described above, according to the present invention, the welding surface of the workpiece to be welded is mounted vertically on the horizontally provided positioning pin, and then the nut is mounted horizontally on the small diameter portion of the positioning pin, and then, When projection welding is performed using a movable electrode that moves horizontally, compressed air is constantly blown diagonally downward onto the nut attached to the positioning pin to hold the nut and prevent it from falling off. Nut projection welding can be easily performed from the horizontal direction on the surface to be welded in the direction. Therefore,
Projection welding of nuts can be easily performed even when the surface to be welded is not horizontal but vertical, so there is no need to rotate the workpiece, such as a car frame, when welding multiple points, which further improves work efficiency. Moreover, it is also economical since there is no equipment cost such as a reversing mechanism.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of the nut welding method according to the present invention, and FIGS. 2 and 3 are front views showing conventional examples of the nut welding method. 1... Workpiece, 1a... Through hole, 2, 5... Electrode, 3... Positioning pin, 4... Nut, 4a...
...Through hole, 6...Compressed air supply nozzle.

Claims (1)

[Claims] 1. A positioning pin provided horizontally on the fixed electrode is vertically attached to the welding surface of the workpiece through a through hole formed in the welding surface, and then a nut is inserted into the small diameter part of the positioning pin. After installing the nut horizontally through the through hole, when performing projection welding by applying pressure with a movable electrode that moves horizontally, the nut installed on the positioning pin is attached diagonally downward. A nut welding method that is characterized by performing projection welding while constantly blowing compressed air from any direction to prevent falling off.