JPH0460749B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a method for sequentially welding a plurality of welded parts, particularly a welding method suitable for welding a box-shaped object to be welded (hereinafter referred to as a workpiece). Regarding.

[Conventional technology]

For example, when welding and assembling a workpiece 1 that will become a microwave oven box as shown in Fig. 4,
Three members 1A, 1B, 1C as shown in FIG.
are prepared in advance, and first, eight flanges 1a, 1b, 1c, and
By temporarily attaching members 1A and 1C to 1B using 1d, 1e, 1f, 1g, and 1h, a workpiece having a structure as shown in FIG. 4 is obtained.

Next, the workpiece 1 temporarily attached in this manner is welded along the welding line shown in FIG. The workpiece 1 is set at a set position on a continuous conveyance device 60, and is conveyed by the conveyance device 60, which is driven intermittently in the direction of the arrow at a predetermined speed, and first stops at the first welding station _X1 . Station x ₁
Resistance welding machines 61 and 62 are installed on both sides of the conveying device 60.
are installed, and the respective electrode portions 61a, 62
a moves forward in the direction of the transport device 60, and projection welds a total of two sides of the workpiece 1, one predetermined side at a time. Similar to the first welding station X ₁ , the second, third and fourth welding stations X ₂ ,
A pair of resistance welding machines 63, 64, 65 are also used for X ₃ and X ₄ .
and 66, 67 and 68 are installed. Further, a turntable 69 for rotating the workpiece 1 by 90 degrees is provided between the second station X ₂ and the third station X ₃ in the transport device 60 .

Therefore, the workpiece 1 is at the second welding station.
At _X2 , a pair of predetermined sides are welded in the same manner as in the case of the first station _X1 . In the process of being transported, it is rotated 90 degrees by the ten table 69, and the third and fourth stations X ₃ and X _{4 are}
In each pair of resistance welding machines 65 and 66,
A pair of predetermined sides 67 and 68 are respectively projection welded in the same manner as described above.
Since such conventional welding lines can perform relatively high welding speeds, they are suitable for welding a large number of workpieces of exactly the same shape and size.

[Problems to be solved by the present invention]

However, it took a lot of time to accurately set the workpieces 1 at a large number of predetermined locations on the conveyance device 60. In other words, the welding machines 61 to 68 are usually quite large and heavy, so in order to freely move the welding machines 61 to 68 themselves in each three-dimensional direction, the equipment would be extremely complex and the cost would be extremely high. Upper and lower electrodes 61a to 6 supported by each arm
8a only moves forward and backward by the set stroke, so when changing the workpiece 1 to a different size or type, it is necessary to align the height, width, and depth of the workpiece 1 depending on the size of the workpiece 1. This had to be done accurately, which took a very long time.

Furthermore, even if there is a considerable margin in the welding speed due to the operating speeds of other devices before and after the conveyance device 60,
The number of welding machines installed is determined by the number of welding locations, which may be uneconomical.

[Means for solving problems]

In this invention, a flexible conveyance device consisting of one or more robots is used, the object to be welded is gripped at the tip of a hand which is a part of the conveyance device, and the hand is then rotated, retreated, advanced and rotated, and the welding The work table rises to support the workpiece set on the lower electrode tip of the machine, and the welding machine is operated in this supported state to automatically weld multiple locations on the workpiece.

[Effect]

Based on the data entered in advance, the transport device works with the work table to accurately set the first welding part to be welded at the predetermined position of the welding machine, and after welding, the workpiece is turned over and welded. At the same time, the work table is supported so that it will not be affected by the pressure between the electrodes during welding, so the transfer device can be quickly set up. You can move on to the next transport operation,
Cycle time can be shortened.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 to 3.

Assuming that the workpiece 1 to be welded is a microwave oven box, the workpiece 1 temporarily attached as described above is set on the starting table 2 with its member 1C facing downward. The starting table 2 has a plurality of positioning members 2a to 2d... at locations corresponding to the size and shape of the member 1C of the workpiece 1,
In the case of a workpiece of a different size or shape, the starting table is replaced with an appropriate positioning member. A transport device 3 such as a robot has two hands 3A and 3B. These hands 3A and 3B
are supported by respective arms (not shown);
Move forward, backward, turn, and rotate by DC servo motor drive.
Perform up and down, left and right movements. Hand 3 of transport device 3
Hands A and 3B are located almost directly in front of the workpiece 1 on the starting table 2, and are in a positional relationship such that the hands 3A and 3B can grip the workpiece 1 when they move forward.
A welding machine 4 and a work table 5 are installed at 90 degrees to the starting table 2 with respect to the vertical axis Y of the conveying device 3. Welding machine 4 is a normal resistance welding machine, and has upper and lower electrode tips 4A and 4B. The upper electrode chip 4A is designed to be able to move up and down. The work table 5 has four positioning members 5a to 5d on its upper surface. These positioning members are adapted to fit the inner wall of member 1B of work 1, and have appropriate tapers (not shown) on the inside so that accurate positioning can be achieved even if there is a slight deviation of work 1. ing. The work table 5 can be moved up and down by a cylinder 6.

A proximity sensor 9 is provided on the end face of the base 4C of the welding machine 4 to detect the presence or absence of the workpiece 1 on the work table 5.

In addition, 7 is another conveyance device equivalent to the conveyance device 3, and 8
is a welding machine equivalent to welding machine 4.

Next, this welding method will be explained.

First, the hands 3A and 3B of the transport device 3 move forward and grip the workpiece 1 on the starting table 2. At this time, the two round protrusions 3Aa and 3Ab attached to the lower surface of the upper hand 3A are connected to the oven door window 1.
It enters Aa from above and ensures a secure grip.
When gripping workpiece 1 is completed, hands 3A and 3B
rises and removes work 1 from starting table 2,
Next, move hands 3A and 3B backward while turning 90 degrees to the left. The proximity sensor 9 detects whether another work is present on the work table 5 at the intermediate position of the 45 degree turn. The position detection of this 45 degree rotation is performed by detecting the angle of the arm using an angle sensor built into the transfer device 3, and this intermediate position of 45 degrees is an angle at which even if there is a workpiece on the work table 5, it will not collide. . If there are other workpieces on the work table 5, the hands 3A and 3
B is immediately stopped and placed in a standby state, and waits until the other transport device 7 finishes discharging the workpiece. If there is no workpiece on the work table 5, the conveyance device 3 will not stop at the 45 degree rotation position.
While moving the hands 3A and 3B up and down, left and right, and moving forward, the flange 1a of the workpiece 1 shown in FIG.
(front plate, long side) to the lower electrode tip 4 of welding machine 4.
Set to B. At this time, the transport device 3 performs handling so that the projections arranged in a line at the center of the flange 1a are correctly positioned at the center of the lower electrode chip 4B.

When the correct setting of the workpiece 1 is confirmed by the sensor 9 provided on the base 4C of the lower electrode tip 4B, the welding machine 4 enters the welding process, the upper electrode is lowered, and welding is performed (FIG. 2). When welding is completed, the upper electrode rises and the hand 3 of the conveying device 3
A and 3B move backward while being raised by their arms, and pull out the workpiece 1 from between the upper and lower electrode chips 4A and 4B.

Next, the hands 3A and 3B are rotated 180 degrees by the arms while holding the workpiece 1 at the position where they have finished retreating. Since the workpiece 1 rotates 180 degrees in the retreated position, the workpiece 1 will not collide with the welding machine 4.
When the workpiece 1 is rotated 180 degrees, the conveyance device 3 operates in the same manner as described above, and the flange 1b of the workpiece 1 is set on the lower electrode chip 4B. When the sensor 7 detects the setting, the work table 5 rises to receive the work 1 at the same height. When this set is confirmed, the hand 3A of the transfer device 3,
3B moves backward by the arm and turns 90 degrees to the right in order to grasp the next workpiece on the starting table 2.

When it is confirmed that the hands 3A and 3B of the transfer device 3 have retreated leaving the workpiece 1 on the work table 5, the upper electrode is lowered to weld the part corresponding to the flange 1b, and the second welding is performed. be exposed.

When the welding is completed, the hand 7 of the conveying device 7
A and 7B move forward with their arms, grasp the workpiece 1 on the work table 5, and move backward to the right side.
Turn 90 degrees. Along with this, the work table 5 is lowered to its original position and stands by.

Eight parts of the workpiece 1 to be welded are welded in the same manner, but the flow of the workpiece will be briefly explained with reference to FIG.

In FIG. 3, I and J are conveyance devices corresponding to 3 and 7 in FIG. 1, respectively, and K, L, and M are also conveyance devices equivalent to these. Further, N and O are welding machines corresponding to 4 and 8 in FIG. 1, respectively, and P and Q are also welding machines equivalent to these.

As can be seen from the above description, the plurality of arrows related to each of the transport devices I to L indicate, from the left side, grasping the workpiece 1 and moving backwards, turning 90 degrees, moving forward, moving backwards, moving the workpiece 1
It shows a 180 degree rotation and forward movement, and in the process, welding machine N welds flanges 1a and 1b of workpiece 1, and welding machine O welds flanges 1c and 1d of workpiece 1.
Flanges 1e and 1f of workpiece 1 are welded by welding machine P.
However, by welding machine Q, flanges 1g, 1 of workpiece 1
h are welded to their respective corresponding parts.

By going through each process as described above, three members 1A, 1B, and 1C as shown in FIG. 5 are automatically welded to obtain a target welded product as shown in FIG. 4. I can do it.

In this way, a straight welding line can be constructed by using four welding machines and five conveyance devices and setting the rotation angle of each conveyance device to 90 degrees, but the rotation angle does not necessarily have to be 90 degrees. Alternatively, it may be possible to detect whether or not there is a previous work on the work table within a certain angle range of rotation.

Note that if the length of all welded parts is approximately equal, the number of welding machines does not necessarily need to be four, and the welding speed will be slower, but if there is only one welding machine, the above-mentioned transport device The work table can be rotated horizontally by 90 degrees by combining these actions. The same applies when there are two or three welding machines.

Furthermore, when using four welding machines and five conveyance devices, a work table is not necessarily required, and the hand of one conveyance device may be passed directly to the hand of the other conveyance device.

〔effect〕

According to the present invention, the conveying device grasps the workpiece, moves backward and turns horizontally by a set angle, moves forward and sets it on the lower electrode of the welding machine, and after welding, moves back and remains at that position. Flip the workpiece,
The workpiece moves forward again to set the workpiece on the lower electrode of the welding machine, while at the same time the work table rises to position and firmly support the workpiece. Therefore, it is extremely flexible, and since the work table firmly supports the workpiece during welding after the workpiece has been reversed, the hand can move away from the workpiece in preparation for the next welding. The speed can be increased, and even if the workpiece is of a different size or type, each table can be replaced and the electrode tip can be replaced, which is very simple. Very effective when welding workpieces.

Further, according to this method, the number of welding machines and conveyance devices to be installed can be determined according to the required welding speed, which is advantageous in terms of economy.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a welding system for carrying out an embodiment of the welding method according to the present invention, and FIG.
Figures 3 and 3 are diagrams for explaining the present invention, and Figure 4 is a diagram for explaining the present invention.
Figures and Figure 5 are diagrams for explaining the workpiece, Figure 6
The figure is a diagram for explaining a conventional welding method. 1...Work, 2...Starting table, 3, 7...
...Transport device, 3A, 3B...Hand, 4,8...
Welding machine, 5... work table, 6... cylinder.

Claims (1)

[Claims] 1. Welding multiple locations on the same plane and on different parallel planes of a box-shaped workpiece using a welding machine, a transport device for the workpiece, and a control device that controls these operations. In the method, the hand of the transport device is moved forward to grip the workpiece, and then the hand is moved back and rotated horizontally by a set angle; the hand of the transport device is moved forward to grip the welding machine. a step of setting the object to be welded on a lower electrode tip; a step of operating the welding machine to weld a first part of the object to be welded; and a step of causing the hand to grasp the object to be welded again.
reversing the object to be welded by moving the hand backward and rotating the hand approximately 180 degrees around the longitudinal axis at that position; moving the hand of the conveying device forward again to place the object to be welded on the lower electrode tip; a step of raising a work table equipped with a positioning member to support the box-shaped object to be welded set on the lower electrode chip; and a step of allowing the hand to release the object to be welded for the next transport operation. a step of operating a welding machine to weld a second welded part on a plane parallel to the first welded part;
A multi-point welding method characterized by comprising at least the following.