JPS59125281A - Spot welding gun - Google Patents

Abstract

PURPOSE:To perform surely and safely spot welding without using many clamping devices unlike in the prior art in a spot welding gun by attaching a stationary electrode to one end of a gun arm, and providing a cylinder device which rotates largely or moves back and forth a movable electrode at the other end. CONSTITUTION:An air cylinder 56 for rotation attached to one end of a C- shaped gun arm 18 of a spot welding device is contracted and an air cylinder 48 for pressurizing is rotated clockwise at a specified angle to open largely the spacing between a movable electrode 52 attached to the top end thereof and a stationary electrode 25 installed at the other end of the arm 18. The side part of a vehicle body floor 9 to be welded is positioned in said spacing. The cylinder 56 is extended to position the electrode 25 and the electrode 52 oppositely to each other on the same axial line and thereafter the cylinder 48 is extended to grasp the floor 9 under pressure by both electrodes 25 and 52. The panels 9b, 9b' of the floor 9 are spot-welded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spot welding gun used for spot welding a deep part of a sloped part or curved part of a vehicle body floor of an automobile, for example.

Conventional spot welding machines include, for example, a multi-welding machine as shown in FIG. This multi welding machine has an electrode mounting bracket 2 fixed on a lower 7-plane base 1 that is driven up and down, a plurality of fixed electrodes 3 fixed on the inclined rim of this electrode mounting bracket 2, and a gun mounted on an upper fixed base 4. A mounting bracket 5 is fixed facing downward, and a stud welding gun 6 is mounted to the lower end of the gun mounting bracket 5. This stud welding gun 6 includes a pressurizing air cylinder 7 fixed to the lower end of the gun mounting bracket 5 with a slight downward tilt, and a movable electrode 8 attached to a piston rod 7a of the pressurizing air cylinder 7. ing.

In such a multi welding machine, the car body floor 9 of the car is supplied onto the gun mounting bracket 5, and after the sloped part 9a of the car body floor 9 is brought into contact with the fixed electrode 3, the lower lifter is By raising the base 1 in stages, the movable electrode 8 can be made to correspond to each of the fixed electrodes 3 in sequence. At each point in time, the pressurizing air cylinder 7
Extend the panels 9b and 9b of the vehicle body floor-9.
' is pressurized and held between the movable electrode 8 and the fixed electrode 3, and after electricity is applied between the fixed electrode 3 and the movable electrode 8, it is held for a certain period of time, the pressurizing air cylinder 7 is contracted, and the fixed electrode 3 is By releasing the pressurized clamping of the panels 9b and 9b' by the movable electrode 8 and the movable electrode 8, the panels 9b and 9b' are spot welded at a plurality of locations on the slope portion 9a.

However, such multi-welding machines are specialized machines used for specific vehicle models, and brackets are formed to match the welding point position (welding position) and the welding point shape (the shape of the welding part). For this reason, if the car model changes and the dot position or shape of the dot part changes, it is necessary to change the size and shape of the brackets. □Therefore, the above-mentioned multi-welder was not versatile.

In view of this point, a spot welding gun as shown in FIG. 2 is a welding machine with versatility.

This spot welding gun has a fixed electrode 11 attached to one end of a substantially U-shaped gun arm 10.
The middle part of the movable arm 12 is pivotally connected to the other end by a shaft 13,
A movable electrode 14 is fixed to one end of a movable arm 12, and a pressurizing air cylinder 15 is interposed between the other end of the movable arm 12 and the other end of the gun arm 10.

In the figure, 16 is a secondary cable fixed to the movable arm 12 and gun arm 10, and 17 is an air hose connecting the pressurizing air cylinder 15 and an air source (not shown).

In such a spot welding gun, the panels 9b and 9b' can be pressurized and clamped and released by expanding and contracting the pressurizing air cylinder 15, and the gun arm 10 can be moved in the three-dimensional direction by applying pressure. The clamping position can be changed arbitrarily.

However, since the above-mentioned secondary cable 16 and air hose 17 were located under the vehicle body floor 9, it took up space for the cable and hose, and the secondary cable 16
There is a risk that the secondary cable 16 or air hose 17 may be cut due to interference with the vehicle body floor 9 or a jig (not shown) that supports it, and in this case, a short circuit or other There was a risk that this could lead to a disaster.

Furthermore, by lifting up the slope portion 9a of the vehicle body floor 9 from below with the movable electrode 14, the panels 9b, 9b'
The movable electrode 14 and the fixed electrode 11 are used to press and hold and shake the vehicle body. floor
9 had to be firmly fixed in place to allow accurate welding. However, for this purpose, there was a problem in that a large number of clamping devices had to be used.

Therefore, in this invention, a fixed electrode is fixed to one end of the curved gun arm toward the other end, and the axis of the pressurizing air cylinder is directed to the -ml side of the gun arm and other parts. The pressurizing air cylinder is pivotally attached to the other end of the gun arm so as to be displaced between positions, a movable electrode is fixed to the piston rod of the pressurizing air cylinder, and the movable electrode and the fixed electrode are opposed to each other. A stopper is provided at one end of the gun arm to prevent the pressurizing air cylinder from rotating to one side when the pressurizing air cylinder is in a state of rotation, and the stopper is interposed between the pressurizing air cylinder and the other end of the gun arm. By using a spot welding gun in which the pressurizing air cylinder is rotated between the two positions using an air cylinder, the air hose, secondary cable, etc. of the air cylinder are placed above the work to be welded during welding. This eliminates the need to provide space for the installation below the workpiece to be welded, and also prevents accidents caused by interference between the workpiece to be welded or the jig that supports it, and secondary cables, air hoses, etc. The present invention is characterized in that it can be prevented from occurring and that accurate spot welding can be performed without using many clamping devices as in the past.

Next, this invention will be explained based on FIGS. 3 to 9.

In FIG. 3, 18 is a gun arm that is curved in a substantially C-shape. A seven flange 19 is integrally formed at one end 18a of the gun arm 18, and a holder 2o is removably fixed to this flange 19 with a bolt 21 and a nut 22. An abbreviated shank 23 is removably fixed to the holder 2° with a bolt 24. One end 23a of this shank 23 is connected to the gun arm 1.
8, and a fixed electrode 25 is integrally provided at the tip of this one end 23a.

A sliding block 26 is removably fixed to the other end 18b of the gun arm 18 by bolt means (not shown) (see FIGS. 3 and 4). On both sides of this sliding block 26, a pair of protrusions 26a + 26 are provided as shown in FIGS. 5 and 6.
a', 26b, 26b' are provided in a protruding manner, respectively, and the protrusion 26a + 26a' + 26b + 26b
Holes 27, 28, 29, and 30 are formed in the holes 27, 28, 29, and 30, respectively. Then, bushings 31, 32, 33, and 34 are fitted into the bushings 31, 32, 33, and 34, respectively, and guide rods 3 are fitted into the bushings 31, 32, respectively.
5 is slidably held, and a guide rod 36 is slidably held in the bushes 33 and 34. Both guide rods 35 and 36 are provided in parallel b, and both ends of the guide rods 35 and 36 are fixed to a cradle 37. This cradle 37 is attached to a movable arm of a welding robot (not shown), and this movable arm is NC-controlled in three-dimensional directions by a microcombeater.

Further, a fixing air cylinder 38 is interposed between the sliding block 26 and the cradle 37. The air cylinder 38 includes an air cylinder chamber 39 formed in the sliding block 26 and a piston 40 slidably fitted into the air cylinder chamber 39. The axis of the air cylinder 38 is provided parallel to the guide rods 35 and 36, and a piston rod 41 integral with the piston 40 is fixed to the cradle 37.

An air supply port 42 is opened in the air/linda chamber 39, and the air supply port 42 is connected to an air source (not shown) via an air hose 43.

A fixing bracket 44 is removably fixed to the upper part of the sliding block 26 with bolts 45. The fixed bracket 44 has a pivot 47 at the middle portion of the rotating bracket 46.
It is pivoted for rotation. Rotating bracket 46
A base portion of a cylinder main body 49 of a pressurizing air cylinder 48 is attached to one end portion 46a of the cylinder body 46a.

Therefore, this pressurizing air cylinder 48 can rotate clockwise or counterclockwise about the pivot shaft 47 in FIG. 3. The axis 50 of this pressurizing air cylinder 48 changes along with the rotational displacement of the pressurizing air cylinder 480.
It can be displaced between a position facing the one end 18a side and a position facing diagonally upward as shown by the two-dot chain line.

51 is a piston rod of the pressurizing air cylinder 48; 52
is a movable electrode attached to the tip of the piston rod 51.

Further, a stopper 53 is not attached to the upper end of the fixed bracket 44. This stopper 53 is adapted to prevent rotation of the other end g46b of the rotary bracket 46 when the rotary bracket 46 is rotated by a predetermined angle in the counterclockwise direction in FIG. That is, when the other end 46b of the rotating bracket 46 comes into contact with the stopper 53,
Rotation is prevented. When this rotation is blocked, the movable electrode 52 faces the fixed electrode 25 on the same axis. In the figure, 54.
55 is an air hose connecting the pressurizing air cylinder 48 and an air source (not shown).

56 is a rotating air cylinder. The cylinder body 57 of the rotating air cylinder 56 is rotatably attached to the fixed bracket 44 by a pivot 58, and the piston rod 59 of the rotating air cylinder 56 is rotatably attached to the rotating bracket 46 via a hinge 60. It is attached. 61
, 62 is an air hose that connects the rotating air cylinder 56 to an air source (not shown); 62 is a conductive bracket that attaches the movable electrode 52 to the piston rod 51;
A secondary cable 4 electrically connects the other end 18b of the gun arm 18 and the bracket 63.

Next, the operation of the spot welding gun having such a configuration will be explained.

Before the start of welding work, the movable electrode 52 is coaxially opposed to the fixed electrode 25 as shown in FIGS. 3 and 7. When starting welding work from this state, first reduce the rotary air cylinder 56 and pressurize the air cylinder 48.
The distance between the movable electrode 52 and the fixed electrode 25 is widened by rotating it clockwise about the axis 50 to the position shown by the dotted chain line in FIG. Next, the movable arm (not shown) of the welding robot is controlled to move in a three-dimensional direction by a microconbeater (not shown), and directed diagonally downward.
The movable electrode 52 and the fixed electrode 25 are positioned substantially above and below, and the space between the movable electrode 52 and the fixed electrode 25 is made to face the side of the vehicle body floor 9. Thereafter, the entire spot welding gun is moved to the side of the vehicle floor 9 and controlled by the microconheater, and the slope portion 9a of the vehicle body floor 9 is moved between the movable electrode 52 and the fixed electrode 25 as shown in FIG. position.

Next, by returning the movable arm (not shown) of the welding robot to the horizontal position and extending the rotating air cylinder 56, the other end 46b of the rotating bracket 46 is moved to the stopper 5.
3, so that the movable electrode 52 and the fixed electrode 25 face each other on the same axis (see FIG. 9).

In addition, during such work, the sliding block 26 is connected to the walls 37a, 37 of the cradle 37 as shown in FIG.
Leave it floating in the middle part of b. As a result, when the gun arm 18 hits the vehicle body floor 9 from the same direction as the axes of the guide rods 35 and 36 when controlling the movement of the spot welding gun, the sliding block 26 slides against the guide rods 35 and 36. The impact force is absorbed by the dynamic displacement.

After the welding position is set by controlling the movement as described above, high pressure air is supplied into the air cylinder chamber 39 to move the sliding block 26 against the guide rods 35 and 36 at the wall portion 37a. The sliding block 26 is pressed and fixed to the wall portion 37a.

Thereafter, the pressurizing air cylinder 48 is extended to press and hold the vehicle floor 9 between the movable electrode 52 and the fixed electrode 25 on the slope portion 9a. In this state, electricity is applied between the movable electrode 52 and the fixed electrode 25, and after holding it for a certain period of time, the pressure clamping is released, and the panels 9b, 9b'
spot weld. Such spot welding is performed at multiple locations A to F in FIG.

In this case, the welding position is changed by stepwise displacing the direction and height of a movable arm of a welding robot (not shown) in three-dimensional directions.

As explained above, the present invention provides a fixed electrode fixed to one end of a curved gun arm toward the other end, and a position where the axis of the pressurizing air cylinder faces the one end of the gun arm. The pressurizing air cylinder is pivotally attached to the other end of the gun arm so as to be displaced between the position facing the part thereof, and a movable electrode is fixed to the piston rond of the pressurizing air cylinder, and fixed to the movable electrode. A stopper is provided at one end of the gun arm to prevent the pressurizing air cylinder from rotating to one side while facing the electrode, and a stopper is provided between the pressurizing air cylinder and the other end of the gun arm. Since the spot welding gun is configured such that the pressurizing air cylinder is rotated between the two positions using the interposed rotating air cylinder, the air hose and secondary cable of the air cylinder are connected to the workpiece to be welded during welding. By arranging it on the upper side, it is possible to eliminate the need to provide a space below the workpiece to be welded, and to connect the workpiece to be welded or the jig that supports it, secondary cables, air hoses, etc. It is possible to prevent disasters from occurring due to interference, and moreover, it is possible to perform accurate spot welding without using many clamping devices as in the past.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a conventional multi welding machine, Fig. 2 is an explanatory diagram of a conventional spot welding gun, Fig. 3 is a side view of the spot welding gun according to the present invention, and Fig. 4 is a portion of Fig. 3. Right side view, Figure 5 is a sectional view taken along the line ■-V in Figure 3, Figure 6 is a sectional view showing the sliding block in Figure 5 fixed to the cradle, Figures 7 to 9 The figure is an explanatory diagram showing the usage state of the spot welding gun of FIG. 3. 9... Vehicle body floor (work to be welded), 9a... Slope portion, 9b, 9b'... Panel, 18... Can arm, 18a... One end, 18b... Other end, 25・・・
Fixed electrode, 44... Fixed bracket, 46... Rotating bracket, 47... Pivot, 48... Pressurizing air/
Lifter, 49... Cylinder body, 50... Axis i, 5
1... Piston rond, 52... Movable electrode, 53...
・Stock tube, 54, 55...Air hose, 56...
Rotating air cylinder, 57... cylinder body, 58...
...Pivot, 59...Piston Rondo, 60...Hinge, 61.62...Air hose, 64...Secondary cable. d1;41s1 18 riS5i-',,'. Body゛261-1 r2'8Q 56 Ri:: 9 r, 1 6 59 (

Claims (1)

[Claims] A fixed electrode is fixed to one end of the curved gun arm toward the other end, and the axis of the pressurizing air cylinder is displaced between a position facing the one end of the gun arm and a position facing the other end. The pressurizing air cylinder is pivotally attached to the other end of the gun arm, a movable electrode is fixed to the piston rod of the pressurizing air cylinder, and the pressurizing air is connected with the movable electrode and the fixed electrode facing each other. A stopper for preventing rotation of the cylinder to one side is provided at one end of the gun arm, and the rotation air cylinder interposed between the pressurizing air cylinder and the other end of the gun arm allows the pressure to be applied. A spot welding gun characterized in that a pressure air cylinder is rotated between the two positions.