JPH03210975A - Automatic welding method and device for small parts - Google Patents

Abstract

PURPOSE:To accurately supply the small-sized parts and to carry out the parts supply and pressure welding with the same motion by using an intermediate electrode arranged insertably between upper and lower electrodes for the parts supply to a narrow part of a weld zone and welding. CONSTITUTION:The small-sized parts B sent to the position close to the upper and lower electrodes 1 and 2 are sucked and held by the intermediate electrode 3 insertable into the narrow part and the intermediate electrode 3 is shifted and the small-sized parts B are transferred onto the pressurization center line of the upper and lower electrodes 1 and 2. After the small-sized parts B along with the intermediate electrode 3 are then lowered to the inside of the narrow part and these are inserted therein by the intermediate electrode 3, the pressurizing force require for welding and a welding current are supplied between the upper and lower electrodes 1 and 2 and the small-sized parts B are welded. Accordingly, since pressure welding can be immediately started in a state with the small-sized parts B sucked and held by the intermediate electrode 3 even for the narrow part with very small width, sure welding can be performed simultaneously with the parts supply.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention involves inserting a small part such as a weld bolt or T-shaped weld nut with a projection on the welding surface into a narrow part of a press work. This invention relates to a method for welding by applying current under pressure between upper and lower electrodes, and a welding device that uses an intermediate electrode that is inserted between the upper and lower electrodes to supply parts to such a gap and perform welding. .

(Prior Art) Conventionally, when supplying a welding bolt to a deep bottom plate or a narrow part such as a container and welding it via upper and lower electrodes, a method such as that disclosed in Japanese Utility Model Application Laid-open No. 106590/1983 has been used. A parts feeding device has been proposed.

In other words, this type of device includes a parts feeding means that sends out welding bolts from a predetermined position, and a chuck device that can be opened and closed to hold the parts directly below the parts feeding means and to move and feed the parts to the welding position. A component feeding device having the above-mentioned chuck device is supported by a chuck feeding mechanism movable in both horizontal and vertical directions.

According to this device, even a bottom plate in a deep place can be supplied by simply lowering the chuck device vertically from above the workpiece and opening the chuck, so welding bolts can be accurately welded without being restricted by the depth or length of the workpiece. It has the advantage of being able to

(Problem to be solved by the invention!! 1) However, as shown in Fig. 5, the gap e in the narrow part of the workpiece W is narrow, and the welding pole) B is supplied to the deep bottom plate f for welding. In this case, since a normal chucking device cannot open the chuck within a narrow space, its application is restricted in such a narrow space between narrow spaces.

(Means for Solving the Problems) Therefore, the present invention takes the following technical means as a means for solving the above problems.

That is, the present invention provides a method for supplying a small part such as a welding bolt or a welding nut to a narrow part of a workpiece and pressure welding it via a pair of upper and lower electrodes. The small part sent to a position close to the narrow part is attracted and held by an intermediate electrode that can be inserted into the narrow part, and the middle electrode is shifted to transfer the small part onto the pressurizing center line of the upper and lower electrodes, and then Provided is an automatic welding method for small parts in which the small part is lowered into the narrow part together with the intermediate electrode, inserted by the intermediate electrode, and then welded by supplying the pressure and welding current necessary for welding between the upper and lower electrodes. do.

Next, as an invention for carrying out the method of the above invention, a small parts feeder, such as a welding bolt or a welding nut, is fed to a position close to a pair of upper and lower electrodes of a resistance welding machine. A feeding device, a member for receiving small parts sent out from the feeding device, a small parts shifting device for shifting this member to a predetermined position, an intermediate electrode for suctioning and holding the small parts in a predetermined position, and this intermediate electrode. To provide an automatic welding device for small parts, characterized in that it is equipped with an intermediate electrode shift device that supports the welding machine so as to be movable up and down, and shifts the small parts held by suction toward the electrode pressurization center line of the welding machine. .

(Function) According to the method and apparatus according to the present invention, small parts can be accurately fed even in narrow gaps by using an intermediate electrode, and moreover, parts feeding and pressure welding can be performed accurately. can be performed in the same motion.

Furthermore, since units such as an intermediate electrode, suction means, and shift device are simply added to the resistance welding machine, the structure is relatively simple and can be manufactured at low cost.

(Example) Hereinafter, the most preferred example as an apparatus for carrying out the method of the present invention will be described based on the drawings.

FIG. 1 is a front view of the device of the present invention. FIG. 2 is also a side view thereof. Moreover, FIG. 3 is a plan view. FIG. 4 is a sectional view of the main part of the intermediate electrode.

Reference numeral 1 indicates the upper electrode of the spot welding machine. 2 is a lower electrode corresponding to the upper electrode 1 on the pressurizing center line (A-A). 3 is the intermediate electrode, whose specific structure is the 4th electrode.
As shown in the figure, the tip of the intermediate electrode holder 4 is provided with chip insertion holes a and b that communicate with the reciprocating paths of the cooling water passages 4b and 4C installed inside the intermediate electrode holder 4, and An upper electrode chip 5 corresponding to the upper electrode 1 is inserted into the chip insertion hole a, and a lower electrode chip 6 corresponding to the lower electrode 2 is inserted into the lower chip insertion hole on the same axis,
These upper and lower electrode chips 5.6 are cooled by cooling water circulating in the reciprocating paths of the cooling water passages 4b and 4C of the intermediate electrode holder 4.

The diameter of the lower electrode tip 6 is the same as the diameter of the head of the welding bolt B, and an air suction port 6a is provided in the center thereof. This air suction port 6a communicates with a vacuum air passage 4a provided inside the intermediate electrode holder 4. Therefore, when the suction port of the lower electrode tip 6 is closed by the head of the bolt B, suction force due to vacuum acts in the space of the suction port due to air suction, and the welding bolt is attracted and held on the pressurized surface of the lower electrode tip. do.

Note that 7 is the lower arm of the welding machine body that supports the lower electrode 2;
is a support stand, which has a welded structure integral with a bracket 8' fixed to the lower arm 7.

The intermediate electrode shift device 10 consists of the following structural parts. That is, a rail 11 supported horizontally on a support base 8, a housing 13 that moves along this rail 11 by the drive of a cylinder 12, and a moving base 14 fixed to this housing 13 in a vertical direction. Bracket 15
A rail 16 supported by this bracket 15, an L-shaped bracket 17 fixed to the side surface of this rail 16, an elevating cylinder 18 fixed downward to this bracket 17, and a drive of this elevating cylinder 18. The above is ~
A housing 19 that moves along a lever 16.

Therefore, the intermediate electrode holder 4 is supported by the housing 19, and can be moved forward in a direction perpendicular to the electrode pressurizing line, and can also be moved up and down.

The small parts shifting device 20 consists of the following structural parts. That is, a rail 21 is fixed to an angle bracket 21 fixed on the support base 8 in a direction perpendicular to the forward movement direction of the intermediate electrode shift device 1°, and a hanging 22 moves on this rail 21. An L-shaped bracket 24 fixed to the hanging 22
A bolt receiving member 25 is fixed to the tip of the bolt. The bracket 24 and the piston rod of the cylinder 23 are connected via a knuckle 26 so that they can be shifted. Therefore, the bolts that have fallen from the hose outlet through the bolt supply pipe 27 from the small parts supply device not shown in the drawings are supplied to the bolt receiving member 25 directly below, and as the cylinder 23 moves forward, the bolts are sent to the intermediate electrode 25 together with the member 25. The structure is such that it is supplied directly below the lower electrode chip 6.

Next, the operation of the device of the present invention will be explained.

The cylinder 12 and the lifting cylinder 18 of the intermediate electrode shift device 10 are retracted, and the intermediate electrode 3 is on standby in the raised position. The cylinder 23 of one of the small parts shifting devices 20 is also waiting at the return position.

In this case, the welding bolts are sorted in advance by a bolt supply device (not shown) and supplied through the bolt supply pipe 27 to the small parts receiving member 25 waiting just below the hose outlet. In this state, press the lower electrode 2
Set to . In this case, the rocket pin of the lower electrode 2 is inserted and set into the positioning hole of the welding position of the press work.

When the start button is pressed after the centering is completed, the welding pole (B) supplied to the component receiving member 25 is advanced by the cylinder 23 of the small component shift device 20 and is supplied directly below the lower electrode tip of the intermediate electrode 3 that is on standby. Ru. When the welding pole) B is directly below the lower electrode tip 6 of the intermediate electrode, the cylinder 18 of the intermediate electrode lowers the intermediate electrode holder 4, and at the same time the vacuum starts, and the lower electrode tip 6 presses the bolt head and opens the air suction port. When 6a is closed, the space is suctioned and the welding bolt is attracted by the suction force generated by the vacuum. Lower electrode tip 6
The intermediate electrode, which has attracted the welding bolt, is raised to a predetermined position by the lifting cylinder 18. and intermediate electrode shift device 1
This is advanced by the cylinder 12 of 0, and the welding bolt is transferred onto the pressurizing center 1tiA (A-A) of the upper and lower electrodes. When the welding bolt enters the pressurizing center line, the upper electrode worker descends in response to a welding start command signal from the welding control device and pushes down the intermediate electrode holder 4 from above.At the same time, the intermediate electrode is also assisted by the lifting cylinder 18. Driven and lowered.

When the intermediate electrode 3 is lowered into the narrow part and the threaded part of the welding pole (B) pushes down the pilot pin of the lower electrode 2 and is supplied to the positioning hole of the workpiece, the intermediate electrode 3 is inserted into the narrow part and the head of the bolt is pressed down. Pressure will be applied on the bottom plate.

Next, the vacuum is stopped, and the pressurizing force and welding current necessary for welding are supplied between the upper and lower electrodes via the intermediate electrode, and bolt welding is performed.

During this welding period, regardless of its operation, the small parts shifting device 20 returns to its original position and prepares for the next bolt supply.

When welding is completed, the upper electrode 1 and the intermediate electrode 3 rise to release the workpiece, and at the same time the intermediate electrode returns to its original position from the pressurizing center line and waits in preparation for the next operation.

Note that in the subsequent series of operations, these mechanical and electrical operations are automatically repeated.

(Effects of the Invention) As described above, the present invention is capable of accurately feeding small parts with the intermediate electrode suctioning and holding them even in extremely narrow gaps, and moreover, pressure welding can be started immediately with the feeding operation. Therefore, reliable welding can be performed at the same time as parts supply.

Further, since only the adsorption means and the shift device are provided on the intermediate electrode, the structure of the feeding unit device is relatively simple and can be manufactured at low cost.

In the embodiments of the present invention, an air vacuum method is used as a means for attracting the intermediate electrode, but the technical idea of the present invention is not limited to this. For example, an electromagnet or a permanent magnet may be used. However, it goes without saying that it is included in the technical scope of the adsorption means in the present invention.

[Brief explanation of drawings]

FIG. 1 is a front view of the most preferred embodiment of the apparatus for carrying out the method of the present invention. Figure 2 is Figure 1 n-
N arrow view. Figure 3 is a plan view. FIG. 4 is an enlarged sectional view of the main part of the intermediate electrode. FIG. 5 is a perspective view including a fractured cross section showing the structure of the object to be welded. [Explanation of symbols] 1.2... Upper and lower electrodes 3... Intermediate electrode 4000. Intermediate electrode holder 10... Intermediate electrode shift Fig. 4

Claims (1)

[Claims] 1. A method of supplying a small part such as a welding bolt or a welding nut to a narrow part of an object to be welded and pressure welding it via a pair of upper electrode and lower electrode, A small part sent to a position close to the upper and lower electrodes is adsorbed and held by an intermediate electrode that can be inserted into the narrow part, and the intermediate electrode is shifted to transfer the small part onto the pressurizing center line of the upper and lower electrodes, Next, the small part is lowered into the narrow part together with the intermediate electrode, and after inserting it with the intermediate electrode,
An automatic method for welding small parts by supplying the necessary pressure and welding current between the upper and lower electrodes. 2. A small parts feeding device that feeds small parts such as welding bolts or welding nuts to a position close to a pair of upper and lower electrodes of a resistance welding machine, and small parts sent out from this feeding device. A member for receiving the small parts, a small parts shifting device for shifting this member to a predetermined position, an intermediate electrode for suctioning and holding the small parts at a predetermined position, and supporting the intermediate electrode so as to be movable up and down, and also for supporting the small parts held by suction. An automatic welding device for small parts, comprising: an intermediate electrode shifting device that shifts the electrode toward the electrode pressurization center line of the welding machine.