JPH0747222B2 - Resistance welding equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resistance welding method and apparatus for electric resistance welding.

[Conventional technology]

In electric resistance welding such as spot welding, a pair of upper and lower electrodes facing each other is used to press an object to be welded, and welding is performed by applying an electric current for a predetermined time. In this case, the second
As shown in the figure, the electrode tips 1 and 2 are directly fixed to the electrode holders 5 and 6, and the shank (also called sleeve) 3, 4
The electrode holders 5 and 6 are used by being fixed to the arms (or horns) 7 and 8 in some cases. When welding with such a structure around the electrodes, if the material to be welded is a general cold-rolled steel sheet, it shows sufficient continuous spotting property (electrode life), but welding of various surface-treated steel sheets including galvanized steel sheets Then, as the number of RBIs increases,
The electrode tip made of a copper-based material and the plated metal of the steel sheet are alloyed with each other, and the tip portion (contact portion with the steel sheet) of the electrode is worn and expanded. For this reason, the current density is reduced, a predetermined nugget is not formed, and the time (number of dots) until dressing or replacement of the electrode tip has to be shortened, resulting in a decrease in productivity.

As means for solving these difficulties, for example, Japanese Patent Laid-Open No. 61-29
3679, Japanese Utility Model Publication No. 61-67978, and the like are known. In the case of this device, an electrode rotating shaft is provided in the direction perpendicular to the electrode pressing shaft, and a plurality of electrode tips are embedded or ring-shaped electrodes are attached around this rotating shaft, and they are intermittently rotated and welded. However, these are large-scaled in terms of equipment, and further, there is a problem that the shape of the object to be welded is considerably restricted due to its structure.

[Problems to be Solved by the Invention]

An object of the present invention is to solve the problems of the conventional welding method and apparatus, and it is an object of the present invention to provide a resistance welding method and apparatus having a high continuous spotting property when welding plated steel sheets and the like.

[Means for Solving the Problems]

 The gist of the present invention is listed below.

(1) The rotation axis and the movement axis of the pair of upper and lower bar-shaped electrode portions facing each other are made non-parallel except at right angles to the pressing axis, and the electrode portion including the electrode tip is used as the rotation axis with the electrode center axis as the rotation axis. A resistance welding device characterized in that a driving source for rotating is arranged via a connecting shaft.

(2) The rotating shaft and the moving shaft of the pair of upper and lower bar-shaped electrode portions facing each other are made non-parallel except at right angles to the pressing shaft, and the electrode portion including the electrode tip is used as the rotating shaft with the electrode central axis as the rotating shaft. A resistance welding apparatus is provided with a mechanism for rotating the electrode using the electrode pressing force and the vertical movement of the electrode by a spring.

(3) The resistance welding device according to (1), wherein a mechanism for rotating the rod-shaped electrode portion using a fluid as a drive source is provided.

(4) The resistance welding device according to (1), wherein a transmission is provided at a connecting portion with a mechanism for rotating the rod-shaped electrode portion using a fluid as a drive source.

(5) The drive source or the rotation mechanism portion for rotating the rod-shaped electrode portion is arranged inside an arm holding the electrode portion, (1), (2), (3). Alternatively, the resistance welding device according to (4).

The present invention will be described below with reference to the drawings together with the operation.

[Work]

In order to facilitate understanding of the present invention, FIG. 2 shows a mode of a conventional electrode peripheral portion. Where the upper and lower electrode tips
The electrode part including 1,2 and shank 3,4 is the electrode holder 5,6
The electrode holder is fixed to the upper and lower arms 7 and 8. Further, in general, the electrode pressing shaft 9 is often the same as the central axis of the electrode.

FIG. 1 shows an embodiment of the present invention. With respect to the electrode pressing shaft 10, the center shafts 11 and 12, which are the rotating shaft and the moving shaft of the pair of upper and lower bar-shaped electrode portions facing each other, are tilted at predetermined angles θ with respect to the pressing shaft 10 except right angles. . Upper and lower electrode tips
The electrode portion including the shanks (also referred to as sleeves) 3 and 4 is intermittently rotated by a predetermined angle α as indicated by arrows A and B with the electrode center axes 11 and 12 as rotation axes. Here, in order to incline the electrode central axis with respect to the pressing central axis, the fixed electrode holder 14 is inclined and fixed to the arm 7 as shown in FIG. 5 or 6.

FIGS. 3 (a) and 3 (b) show an example of an embodiment of the electrode portion having a rotating function described in the first claim of the present invention. The electrode tip 1 is fixed to the rotary electrode holder 13. The rotating electrode holder 13 is connected to the non-rotating fixed electrode holder 14 via the rotary sliding portion 16 for rotating the central axis 11 of the electrode as a rotating shaft, and the fixed electrode holder 14 is fixed to the arm 7. deep. A rotating electrode holder 13 is provided at the center of the electrode section.
Although a water cooling pipe 15 fixedly attached to the solid electrode holder is provided, the connecting portion between the rotary electrode holder 13 and the solid electrode holder 14 is O (o) so that the water for cooling the electrode tip 1 does not leak to the outside.
Seal with rings 17 and 18. In addition, as shown in FIG. 3 (b), the structure is such that a flowing water path can be always secured even if the rotating electrode holder 13 rotates. Further, since the rotating electrode holder 13 and the fixed electrode holder 14 pass the welding current through the rotary sliding portion 16, the rotating electrode holder 13 and the fixed electrode holder 14 are connected to each other so that sufficient electric conductivity can be secured.

A motor 21 such as a stepping (pulse) motor or a servomotor is arranged on the fixed electrode holder 14 via the motor support 20 in order to rotate the electrode tip 1 and the rotating electrode holder 13. Here, the fixed electrode holder 14 and the motor 21 are electrically insulated by an insulator 19 so that a welding current does not flow in the motor. The drive connecting shaft, in this case the motor shaft (spindle) 22, is fixed to the rotating electrode holder 13 via the insulator 23, and the rotating electrode holder 13 is rotated as the motor shaft 22 rotates.

In this case, although not shown, a well-known driver (controller) is used to control the timing of rotating the motor 21 or the amount of rotation (angle). In this case, the rotation timing (rotation frequency: times / point), rotation angle, rotation direction, and other settings are preset, but a signal that detects the vertical movement of the electrode, a welding signal, or a counter that counts the number of dots. Alternatively, the output signal may be controlled. The rotation of the electrode portion is not performed at least when the electrodes sandwich the object to be welded, but is performed in a state where the electrodes are separated from each other.

Although FIG. 3 (a) exemplifies a state in which the motor shaft 22 is arranged on the center axis of the electrode, the present invention is not limited to this.
It may not be perpendicular to the electrode center axis or the electrode center axis, but may be inclined. In this case, a well-known driving force transmission means other than a key gear such as a worm gear and a bevel gear may be used, and a speed reducer may be arranged for mechanical connection between the motor shaft 22 and the rotary electrode holder 13.

The inclination angle θ of the electrode holder can be freely set in the range of 0 ° to less than 90 °, but the proper angle is 5
The rotation angle α of the electrode part can be freely set in the range of 0 degrees to 360 degrees.
It is 10 to 70 degrees. On the other hand, the frequency of electrode rotation is once per point
It can be set freely within a range of once / several thousands, but among these, the proper rotation frequency is once / one point to once / 500 points.

The direction of electrode rotation is illustrated in FIG. 1 as a case of rotating in the same direction as indicated by arrows A and B, but it is not limited to this, and mutual electrodes may be rotated in opposite directions.
Further, regarding the rotation angle and the rotation timing, the electrodes do not necessarily have to be the same.

With such a configuration and method of the electrode peripheral portion, the object to be welded is sandwiched between the upper and lower electrode tips, pressed, and energized for a predetermined time to perform welding.

FIG. 9 and FIG. 10 show an example of an embodiment of the electrode portion having a rotating function described in claim 2 of the present invention. Electrode tip 1
Is fixed to the rotary electrode holder 13. Since the rotating electrode holder 13 rotates about the central axis 11 of the electrode as a rotating shaft, the rotating electrode holder 13 does not rotate through the rotary sliding portion 16 and does not rotate.
The fixed electrode holder 14 is fixed to the arm 7 in advance. A water cooling pipe 15 fixed to a fixed electrode holder 14 is provided at the center of the conductive portion, but the rotating electrode holder 13 is provided so that water for cooling the electrode tip 1 does not leak outside.
And the rotary sliding part of the fixed electrode holder 14 with O-ring
Seal with 17. Further, since the rotating electrode holder 13 and the fixed electrode holder 14 pass the welding current through the rotary sliding portion 16, the rotating electrode holder 13 and the fixed electrode holder 14 are connected to each other so that sufficient electric conductivity can be secured.

A pin guide groove 30 is provided in the rotating electrode holder 13 for rotating the electrode tip 1 and the rotating electrode holder 13.
A rotation guide pin 31 is movably arranged on the fixed electrode holder 14 and is held by a leaf spring 32. A coil spring 28 is inserted between the rotary electrode holder 13 and the fixed electrode holder 14 so that the repulsive force always acts. Furthermore, the rotating electrode holder 13 is a fixed electrode holder.
The stopper ring 29 is arranged on the fixed electrode holder 14 so as not to fall off from the stopper 14.

Rotation of the rotating electrode holder 13 depends on the electrode pressing force and the central axis.
The vertical movement of the electrode with 11 as the movement axis is used, and its action will be described in detail with reference to FIGS. 9 and 10 (a) and (b). 10 (a) is a side view of the pin guide groove portion, and FIG. 10 (b) is a sectional view taken along the line AA of FIG. 10 (a).

Of the configuration of the electrode section shown in FIG. 9, FIG. 10 (a) (b)
As will be shown in detail, the rotation guide pin 31 provided in the fixed electrode holder 13 is slidably combined with the pin guide groove 30 provided in the rotary electrode holder 13. The pin 31 is located at m1 before welding and pressurization, but the pin 31 moves to m2 when a pressing force is applied. After the predetermined welding is performed in this state, the pressure is released and the electrode rises. At this time, the pin 31 tries to return to its original state due to the action (repulsive force) of the spring 28, but the pin 31 is disturbed by the step provided in the guide groove 30 and cannot return to m1. Moving. As a result, the pin 31 moves from m1 to m3 by the distance d by one welding (up and down movement of the electrode).

In FIG. 10, it is explained that the guide pin 31 is moved for easy understanding, but since the guide pin 31 is actually arranged on the fixed electrode holder 14 side, the guide groove
30 moves a distance d. Since the guide groove 30 is carved in the rotary electrode holder 13, the rotary electrode holder 13 is separated by a distance d.
Will be rotated by the amount equivalent to. Here, for example, the moving distance d is 1 / the total length of the circumference of the rotating electrode holder.
When it corresponds to 6 (the number of bends in the guide groove: 6), the electrode 1 rotates by 60 degrees in one welding. Therefore, the rotation angle of the electrode 1 is determined by the number of bends of the guide groove 30 arranged on the rotating electrode holder 13 side.

It should be noted that the repulsive force of the spring 28 is set to a level sufficiently smaller than the normal electrode pressing force, while the spring is selected so as to have a repulsive force sufficiently larger than the sliding resistance of the rotary sliding surface 16. Therefore, it is preferable that the rotary sliding surface 16 has as small a sliding resistance as possible while ensuring electrical conductivity. However, when the pressing force is applied, the end 13a of the rotating electrode holder 13 is opposed to the fixed electrode holder 1 against the repulsive force of the spring.
The structure is crimped to the wall surface 14a of 4 and sufficient electrical conductivity can be ensured only by this crimped portion.

Here, the action on the movable electrode side (generally the upper electrode) is illustrated, but the same action also works on the lower electrode side. Further, the rotating direction of the electrodes may be the same as that of the upper and lower electrodes, or may be the opposite direction. In contrast to FIG. 9, guide pins may be arranged on the rotating electrode holder 13 side and guide grooves may be arranged on the fixed electrode holder 14 side.

Although the combination of the square groove and the pin is illustrated in FIG. 10, the present invention is not limited to this, and a known means such as a combination of the round groove and the guide ball 33 illustrated in FIG. 11 may be used. Also, the tenth
In the figure, a guide groove with a step is shown as an example in order to ensure the movement of the pin, but the present invention is not limited to this, and as shown in FIG. 12, the force of the electrode and the repulsive force of the spring are used. As long as the pin 31 can move reliably in the guide groove 30, any other known groove shape may be used.

A mode in which the rotating action of the electrodes is carried out by using a cam mechanism is shown in FIGS. 13 (a) and 13 (b). For the cams 35 and 36 arranged on the rotating electrode holder 13, the fixed electrode holder 14
A cam 34 is installed on the fixed electrode holder 14
The pin 37 is arranged on the sleeve 38 fixed by 39.
The sleeve 38 serves as a stopper and a pin for preventing the rotating electrode holder 13 from coming off from the fixed electrode holder 14.
It has the effect of holding 37 in place. Here, the cam 34 acts on the cam 35, and the pin 37 acts on the cam 36.

Due to the repulsive force of the coil spring 28, the normal cam and pin states are as shown in FIG. 13 (b).
The rotating electrode holder 13 moves due to the welding pressure and the cam 35
And the cam 34 of the fixed electrode holder are in contact with each other, and the cam 35 and the cam 35 are pressed against each other while the cam 35 rotates and moves according to the inclination of each other. At this time, the cam 36 and the pin 37 are separated from each other. Predetermined welding is performed in this state. When welding is completed and the electrode rises, the spring
The repulsive force of 28 causes cams 34 and 35 that have been meshed until then.
Are separated from each other, and the cam 36 and the pin 37, which have been separated from each other, come into contact with each other, so that the rotary electrode holder 13 moves and rotates along the inclination of the cam 36. With this series of operations (one welding), the rotary electrode holder 13 is moved / rotated by the distance d.

Here, for example, when the moving distance d corresponds to 1/6 with respect to the entire circumference of the rotating electrode holder (the number of teeth of the cam: 6), 1
Electrode 1 will rotate 60 degrees by welding once. Therefore, the rotation angle of the electrode 1 is determined by the number of teeth of the cam 35 arranged on the rotating electrode holder 13 side. Further, the number of teeth of the cam 34 and the number of pins 37 arranged on the fixed electrode holder 14 side are
It can be freely selected within the range of 1 or more and the same number as the number of teeth of the cams 35, 36. It should be noted that although the rotation operation by the combination of the cam and the pin has been illustrated here, the invention is not limited to this, and any other known cam mechanism or ratchet or any other means for converting linear motion into rotary motion in one direction Good.

It should be noted that the repulsive force of the spring 28 is set to a level sufficiently smaller than the normal electrode pressing force, while the spring is selected so as to have a repulsive force sufficiently larger than the sliding resistance of the rotary sliding surface 16. Therefore, it is preferable that the rotary sliding surface 16 has as small a sliding resistance as possible while ensuring electrical conductivity.

In the example of the embodiment of the present invention shown in FIGS. 9 to 13, the case where the electrode rotation mechanism is arranged in the electrode holder has been described in detail, but the arrangement position of the rotation mechanism is not limited to this. Instead of the one, it may be arranged on the shank or the arm.

The inclination angle θ of the rotary electrode holder 1 can be freely set in the range of 0 ° to less than 90 °, but the proper angle is 5 ° to 30 °, and the rotation angle α of the electrode part is a guide. It can be freely set in the range of 10 degrees to 180 degrees depending on the number of bent portions of the groove or the number of teeth of the cam, but the proper angle is 30 degrees to 90 degrees.

The direction of electrode rotation is illustrated in FIG. 1 as a case of rotating in the same direction as indicated by arrows A and B, but it is not limited to this, and mutual electrodes may be rotated in opposite directions.
Regarding the rotation angle, the electrodes do not necessarily have to be the same.

With such a configuration and method of the electrode peripheral portion, the object to be welded is sandwiched between the upper and lower electrode chips and pressed to carry out energization and welding for a predetermined time.

14 (a) (b) (c), FIG. 15 and FIG. 16 show an example of an embodiment of the electrode portion having a rotating function described in claim 3 of the present invention.

In FIG. 14A, the electrode chip 1 is fixed to the rotary electrode holder 13. The rotary electrode holder 13 has a central electrode shaft 11
Via the rotary sliding portion 16 to rotate the
The fixed electrode holder 14 is fixed to the arm 7 by joining with the fixed electrode holder 14 which does not rotate. A water cooling pipe 15 fixed to the rotating electrode holder 13 is arranged at the center of the electrode portion, but the rotating electrode holder 13 and the fixed electrode holder are arranged so that the water for cooling the electrode chip 1 does not leak outside. The connection part of 14 is sealed with an O-ring 17. The water flow structure B has the structure shown in FIG. 3 (B) so that the flowing water path can always be secured even when the rotary electrode holder 13 rotates. In addition, the rotating electrode holder 13 and the fixed electrode holder 14
Means that a welding current is passed through the rotary sliding portion 16 so that a sufficient electric conductivity can be secured. Further, a stopper ring 29 is arranged on the fixed electrode holder 14 so that the rotating electrode holder 13 does not fall off from the fixed electrode holder 14.

In order to rotate the electrode tip 1 and the rotating electrode holder 13, the rotating electrode holder 13 has a water wheel (impeller) 40 at the cooling water supply portion.
Is provided. The appearance of the water turbine 40 is shown in Fig. 14 (b),
FIG. 14 (c) is a sectional view taken along line AA of FIG. The water wheel 40 receives the momentum (energy) of the water for cooling the electrode tip 1 flowing into the electrode section, whereby the water wheel 40 rotates in a certain direction. Since the water wheel 40 is fixed to the rotating electrode holder 13 and the electrode tip 1 is fixed to the rotating electrode holder 13, the rotation of the water wheel 40 is the rotation of the electrode tip 1 as it is. The cooling water that has acted on the water wheel 40 flows into the water passage hole provided in the central axis of the water wheel 40, cools the electrode tip 1, and is then discharged.

In general, the cooling water for the electrode tips is constantly flowed while the welding machine is in operation, so the upper and lower electrode tips are always rotating. However, during welding, a pressure force acts on the electrode tip 1 and a force far greater than the force that the running water rotates the water turbine 40 exerts on the electrode tip. Therefore, the electrode tip does not rotate during pressurization, and the stationary state. Becomes In this state, predetermined welding energization is performed. Next, after a lapse of a predetermined holding time, the electrode is raised and one time (one point) of welding is completed. At the same time as the pressure applied to the electrode tip is released, the electrode tip 1 starts to rotate again due to the action of the cooling water.

In this mechanism, the electrode is constantly rotating and is stationary during welding, but the rotation angle and the number of rotations are completely random.
The rotation speed is determined by the sliding resistance of the rotary sliding portion 16, the flow rate of cooling water, the shape of the water wheel 40, and the like.

FIGS. 15 and 16 show the structure of the peripheral portion of the water turbine 40, which is a means for intermittently rotating the electrode tip 1. 15th
In the figure, a solenoid valve 43 is provided in the cooling water supply path, and the flow path is configured to be switched as indicated by arrows C and D. When the cooling water flows in the direction of arrow C, it acts on the water wheel 40 and the electrodes rotate. On the other hand, when the electromagnetic valve 43 is switched and the cooling water flows in the direction of the arrow D, the cooling water flows directly into the central axis of the water wheel 40, so that the water wheel 40 is not rotated and is discharged after the electrode cooling. That is, the rotation frequency can be controlled by a combination with a known solenoid valve, and there is no problem in cooling the electrodes.

In FIG. 16, the central axis of the water turbine 40 is extended to serve as a spindle 45, which is projected to the outside through an end plate with an O-ring. A brake 46 having a known mechanism is arranged on the spindle 45. The electrode rotation can be controlled by applying the brake 46 at a predetermined timing.

FIG. 17 shows an example of a mode in which a transmission is arranged at the connecting portion between the electrode portion and the rotating mechanism described in claim 4 of the present invention.

In FIG. 17, a hollow spindle 53 fixed to the central shaft 11 of the rotating electrode holder 13 arranged inside the fixed electrode holder 14 is shown.
Worm wheel on (extended water cooling pipe 15)
Stick out 47. The worm wheel 47 is provided with a worm 48 forming a pair with the worm wheel 47. The water turbine (impeller) 40 is fixedly attached to the spindle 49 of the worm 48. The water turbine 40 is surrounded by a case 50 having a structure in which running water does not leak, and water supply pipes 51 and 52 are connected to the case 50.
The cooling water for rotating the water wheel 40 is the water wheel as indicated by arrow E.
A rotating action is given to the water turbine 40 through a water supply pipe 51 to the water turbine 40. The cooling water that has rotated the water turbine 40 flows to the hollow spindle 53 as shown by the arrow F via the water supply pipe 52 to the electrode, and FIG.
After the electrode tip 1 is cooled as described in detail in Section 2, the water is drained. When the flow rate of the cooling water is low by disposing a transmission such as the worm gear (a pair of worm wheel and worm) illustrated in the connecting portion between the water wheel 40 and the rotating electrode holder 13 as described above. , Or rotating sliding part 16
Even if the sliding resistance is large, the rotating electrode holder 13 can be easily rotated. If the water flow is sufficient, the water turbine 40 can be downsized.

Here, the case of a worm gear having a staggered gear is illustrated as the transmission, but the invention is not limited to this, and the same rotary shaft gear (harmonic drive), parallel shaft gear (spur gear), cross shaft gear ( Rotating shaft 11 of hollow spindle 53 and rotating shaft of turbine 40 (spindle 49)
The combination of can be freely selected. The transmission may be any known gear, such as a belt or a chain, in addition to various gears.

In addition, the rotating mechanism portion provided with the transmission as described above is operated by changing the flowing water path described in detail in FIG. 15 to control the electrode rotation, and by applying the brake described in detail in FIG. Of course, there is no problem even if the means for controlling the electrode rotation is used together.

FIG. 18 shows an example of an embodiment in which a rotating mechanism section for rotating an electrode is arranged inside an arm for holding a fixed electrode, which is described in claim 5 of the present invention.

In FIG. 18, the fixed electrode holder 14 is fixed to the hollow arm 54 in advance. Hollow spindle 53 fixed to central shaft 11 of rotating electrode holder 13 arranged inside fixed electrode holder 14.
Project inside the hollow arm 54 (hollow portion). On this hollow spindle 53, a rotation mechanism section 55 composed of a worm gear and a water wheel, which are described in detail in FIG. 17, is arranged. The water supply / drainage pipe for the cooling water used for rotating and cooling the electrode is connected to the outside at an appropriate point via the inside (hollow portion) of the hollow arm. With such a structure, it is possible to avoid a complicated shape around the electrode portion or to effectively use the welding work space.

Here, the case where the rotation mechanism portion 55 is arranged inside the hollow arm 54 is illustrated, but the present invention is not limited to this. That is, a motor as a drive source for electrode rotation as described in detail in FIG. 3 (a) may be disposed inside the hollow arm 54, or the motor may be installed near the welder main body or a fixed portion of the arm. In this case, a driving force transmitter such as a flexible wire may be passed through the inside of the hollow arm and connected to the rotation mechanism section.

Although the case where the cooling water is used as the fluid for rotating the water turbine 40 is illustrated, the fluid that can be used here is not limited to water, and for example, air, a gas such as nitrogen gas, or an alcohol such as ethylene glycol. Any fluid having a cooling effect, such as oils such as cutting oil and a mixture thereof with water, may be used.

The inclination angle θ of the electrode holder can be freely set in the range of 0 ° to less than 90 °, but the proper angle is 5
The rotation angle α of the electrode portion is 0 to 36 degrees when the mechanism capable of controlling the rotation angle as shown in FIGS. 15 and 16 is used.
It can be set freely within the range of 0 degrees, but the proper angle is 10 to 70 degrees.

On the other hand, the frequency of electrode rotation can be freely set in the range of once / point to once / thousands of points when a mechanism capable of controlling the rotation frequency is used as shown in FIGS. 15 and 16. However, among them, the proper rotation frequency is once / point to once / 500 points.

The direction of electrode rotation is illustrated in FIG. 1 as a case of rotating in the same direction as indicated by arrows A and B, but it is not limited to this, and mutual electrodes may be rotated in opposite directions.
Also, regarding the rotation angle and the rotation timing, the electrodes do not necessarily have to be the same.

With such a configuration and method of the electrode peripheral portion, the object to be welded is sandwiched between the upper and lower electrode tips, pressed, and energized for a predetermined time to perform welding.

FIG. 4 shows the present invention in FIGS. 1, 3 and 9-18.
The top view of an electrode tip front-end | tip part when welding is implemented using the apparatus detailed in the figure is shown. With respect to the point P _{0 at the} center of the surface of the electrode tip end portion 24, the center point P ₁ of the contact portion with the workpiece is eccentric by an amount given by the angle θ, and the contact surface (current-carrying surface) with the workpiece 25 Are formed at offset positions. In this state, when the electrode is rotated by a predetermined angle α or at random at intervals of one or several hundreds of dots, the center of the contact portion moves to P ₁ and a new contact surface 26 is formed. . This operation is sequentially repeated to move the contact surfaces one after another.

As means for inclining the electrode center axis with respect to the pressing axis, as shown in FIGS. 5 and 6, a method of attaching the fixed electrode holder 14 to the arm 7 by inclining, a portable spot welding machine of FIG. Even in the case where the arm itself is bent like the arm 7, the structure can be applied if the fixed electrode holder can be attached.

Further, although an example of the spot welding machine having a pair of electrodes facing each other has been described in FIG. 1, the applicable electrode arrangement and the welding machine are not limited to this. For example, the 8th
When the electrode 27 on one side as shown in the figure has a flat shape, only one of the electrodes needs to be rotated, and the welding machine can be widely applied such as a series spot welder, a multi-spot welder, and a portable spot welder. .

In the conventional welding apparatus, since the welding is performed at the electrode contact surface at a certain position, the contact area increases with an increase in the number of hitting points and the current density decreases, and finally a predetermined nugget is not formed. For example, it can be welded using a normal electrode tip without any change from conventional welding work, and even if the contact surface with the workpiece is alloyed with the plated metal of the steel plate to enlarge the area a little, it is set in advance. For each RBI,
Alternatively, the contact area moves one after another at each impact point, and the new contact area deforms (shapes) the previous contact area, so even if the electrode tip is alloyed, the contact area hardly expands. There is little decrease, and the number of continuous dots (electrode life) is dramatically improved.

As described above, the device having a mechanism for rotating the electrode part by making the rotating shaft and the motion shaft of the pair of upper and lower bar-shaped electrode parts facing each other non-parallel to each other except the right angle with respect to the pressurizing shaft improves the continuous dot performance. It plays an extremely important role.

〔Example〕

Examples of continuous spotting properties of the spot welding method according to the present invention will be described below.

The material to be welded is hot-dip galvanized steel sheet with a thickness (t) of 0.8 ml 150/1
Two sheets of 50 (g / m ² ) were used. The welding conditions are summarized below.

・ Welder: Stationary spot welder 60KvA. Electrode shape: Radius piece (15R), D = 16mmφ. Pressurizing force: 200 kg ・ Electrification time: 10 cycles ・ Welding current: Scattering limit current value (10300 ± 500 A) ・ Dot pitch: 15 mm. Dotting speed: 1 point / 2 seconds For continuous dotability evaluation, a test piece for nugget diameter measurement is sampled every 100 points welding, Is the maximum number of welding points. Tables 1, 2, and 3 show the detailed welding conditions and the continuous spotting property evaluation results of the method of the present invention in comparison with the conventional method.

That is, Table 1 shows the continuous dot evaluation results when the motor was used as the drive source for electrode rotation.
Compared to No. 1), in the method of the present invention (Test Nos. 2 to 6),
The number of continuous runs has been greatly improved.

In addition, Table 2 shows the results when the vertical movement of the electrode was used as the drive source for the electrode rotation, and both the guide groove method (test No. 7 to 9) and the cam method (test No. 10 to 12) were used. Was significantly higher than the conventional method.

Table 3 shows the results when the cooling water flow was used as the driving source for the electrode rotation, and the method of the present invention (Test Nos. 13 to 20, cooling water amount: 2.5 / min) was used even if the rotation stopping method was changed. The number of continuous dots was greatly improved compared to the comparative example.

[Effects of the Invention] As is clear from the results shown in Tables 1, 2, and 3 above, the resistance welding apparatus of the present invention is applied to resistance welding of various surface-treated steel plates including plated steel plates. As a result, there is no electrode welding on the work piece, and although some auxiliary equipment is required around the electrode part, welding can be performed without any change from conventional welding work, and the electrode wear due to the increase in the number of dots Since the part moves while shaping it, a nugget of a certain size is formed, and since the number of continuous welding points increases remarkably compared to the conventional welding method, it has a great effect on industrial use such as improvement in production efficiency. To bring.

[Brief description of drawings]

FIG. 1 is a side view of an electrode peripheral portion showing an aspect of the method of the present invention, FIG. 2 is a side view showing an aspect of a conventional electrode portion peripheral device, and FIG.
FIG. 3A is a partial cross-sectional side view showing an embodiment of the electrode part of the device of the present invention, FIG. 3B is a sectional view taken along line AA of FIG. 3A, and FIG. 4 is an embodiment of the present invention. A plan view of the electrode tip, showing
FIG. 5 is a side view showing a mounting mode of the fixed electrode holder, FIG. 6 is a front view showing a mounting mode of the fixed electrode holder, and FIG. 7 is an arm mode of the portable spot welding machine and mounting of the fixed electrode holder. FIG. 8 is a side view showing the mode of FIG. 8 and FIG. 8 is a side view showing the mode when one of the electrodes is a flat electrode. 9 is a partial cross-sectional side view showing another embodiment of the electrode portion of the device of the present invention, FIG. 10 shows the guide groove and guide pin embodiment of FIG. 9, and FIG. 9 (a) is a side view, FIG. 11B is a sectional view taken along the line AA of FIG. 11A, FIG. 11 is a sectional view showing another aspect of FIG. 9, and FIG. 12 is a side view showing another form of the guide groove of FIG. 13 shows another embodiment of the electrode part of the device of the present invention, FIG. 13 (a) is a side view, FIG. 13 (b) is a side view showing a cam and pin mechanism part, and FIG. 14 is a device of the present invention. The other aspect of the electrode part of is shown, (a) is a partial cross-sectional side view,
15B is a perspective view showing the rotation mechanism section, FIG. 15C is a sectional view taken along the line AA of FIG. 15A, and FIG. 15 is another mode of the rotation mechanism section of the apparatus of FIG. FIG. 16 is a cross-sectional view showing another embodiment of the rotating mechanism portion of the device of FIG. 14, FIG. 17 is a perspective view showing another embodiment of the electrode portion of the device of the present invention, and FIG. [Fig. 4] is a side view showing a mode in which a rotation mechanism section is attached in an arm. 1,2 …… electrode tip, 3,4 …… shank, 5,6 …… electrode holder, 7,8 …… arm, 9 …… pressurizing shaft, 10 …… pressurizing shaft, 11,12 …… electrode Central shaft, 13 …… Rotating electrode holder, 14 …… Fixed electrode holder, 15 …… Water cooling pipe, 16 …… Rotating sliding part, 17,18 …… O-ring, 19 …… Insulator, 20 …… Motor Supports, 21 …… Motor, 22 …… Motor shaft, 23 …… Insulator, 24 …… Electrode tip end surface, 25,26 …… Contact surface with the workpiece, 27 …… Flat electrode, 28 …… Coil spring, 29 …… Stopper ring, 30 …… Pin guide groove, 31 …… Rotating guide pin, 32 …… Leaf spring, 33 …… Guide ball, 34 …… Camera on fixed electrode holder side, 35, 36 ...... Rotating electrode holder side cam, 37 ...... Cam positioning pin, 38 ...... Sleeve (pin holder and stopper), 39 ...... screw, 40 ...... water turbine, 41 ...... end ・Rate, 42 ... end plate with water cooling hole, 43 ... solenoid valve, 44 ... end plate with O-ring, 45 ... spindle, 46 ... brake, 47 ... worm wheel, 48 ... worm, 49 …… Worm spindle, 50 …… Turbine case, 51, 52 …… Water supply pipe, 53 …… Hollow spindle, 54 …… Hollow arm, 55 …… Rotating mechanism.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-123479 (JP, A) JP-A-61-293679 (JP, A) Actually open 61-36382 (JP, U) Actual-open Sho 61- 67978 (JP, U) Japanese Patent Sho 55-39435 (JP, B2) Japanese Official 57-59273 (JP, Y2)

Claims (5)

[Claims] 1. A pair of upper and lower rod-shaped electrode parts facing each other are made non-parallel to each other except a right angle with respect to a pressing axis, and an electrode part including an electrode tip is rotated about an electrode center axis. A resistance welding device characterized in that a drive source for rotating as a shaft is arranged via a connecting shaft. 2. A pair of upper and lower bar-shaped electrode portions facing each other are made non-parallel to each other except a right angle with respect to a pressure axis, and the electrode portion including an electrode tip is rotated about an electrode central axis. A resistance welding device characterized in that a mechanism for rotating the shaft by utilizing the electrode pressing force and the vertical movement of the electrode by a spring is provided as a shaft. 3. A resistance welding apparatus according to claim 1, further comprising a mechanism for rotating the rod-shaped electrode portion using a fluid as a drive source. 4. The resistance welding apparatus according to claim 1, wherein a transmission is disposed at a connecting portion with a mechanism for rotating the rod-shaped electrode portion by using a fluid as a drive source. 5. A drive source or a rotation mechanism portion for rotating the rod-shaped electrode portion is arranged inside an arm for holding the electrode portion. Resistance welding equipment.