JPH0910952A - Spot welding gun - Google Patents

Abstract

PURPOSE: To bring electrodes close to, and away from each other, and to surely and oppositely retract the electrodes. CONSTITUTION: A cylinder 3 to which a piston 43 is fitted is formed in an equializing block 4, and inserted with an equializing rod 7 of a bracket 5. An electrode 1 is eccentrically provided with respect to the axis of a piston rod 42, while an electrode 2 is provided in the equalizing block 4 through an insulation material 8. A closed part 52 having a notch 51 is formed in the piston 43, and a vane is provided on the piston. The working fluid to be through a port 13 expands/drives the piston 43 by jetting it from an opening 60 to make the electrodes 1, 2 distant from a work. When the working fluid is ejected also from an opening 61 and hits the vane 44, the piston rod 42 is turned, and the electrode 1 is moved along the turning locus around the axial line of the piston rod from the state of facing the electrode 2, and retracted so as not to interfere with a work W.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spot welding gun. More specifically, the present invention relates to a spot welding gun, and more specifically, a facing position where electrodes are opposed to each other so as to clamp and press a work, and a retracted position where electrodes are retracted so as not to interfere with the work. It concerns a spot welding gun that can be moved to and.

[0002]

2. Description of the Related Art In a spot welding gun, a work is sandwiched between a pair of electrodes facing each other, a large current is applied to the contact resistance between the electrodes in a pressurized state, and the welding is performed by the generated Joule heat.

As an example of a general spot welding gun, as shown in FIGS. 9 and 10, a rod 81 is movably inserted into a base 80, and a cylinder is provided via a pivot 82.
83 and yoke 84 are provided on the rod 81 so that they can swing
There is known a spot welding gun in which a reaction finger 85 is adjustably provided in 80 and a pin 86 which engages with the reaction finger 85 is provided in a piston rod 83a. The upper stabilizer block 87 is located at the rear end of the cylinder 83.
A lower stabilizer block 88 that receives the upper stabilizer block 87 is provided at the rear end of the rod 81, and a stabilizer spring 89 that urges the lower stabilizer block 88 to seat the upper stabilizer block 87 is provided. .

When welding, this spot welding gun is provided on the piston rod 83a by supplying a working fluid such as compressed air to the cylinder 83 so as to extend the piston rod 83a, as shown in FIG. Electrode adapter 90
The electrode 91 at the tip of is placed close to the electrode 92 provided on the yoke 84, and the work W is sandwiched and pressed by both electrodes 91, 92.

After the welding is completed, the cylinder 83
The piston rod 83a is retracted to separate the electrodes 91, 92 from each other. When the pin 86 provided on the piston rod 83a comes into contact with the reaction finger 85, as shown in FIG. 10, the cylinder 83 and the yoke 84 are tilted with respect to the pivot shaft 82 with respect to the base 80 against the stabilizer spring 89. The work W is swung so that the work W is not interfered with.

The adjustment by the mounting direction of the spot welding gun and the positioning of the electrodes 91, 92 with respect to the work W are performed by adjusting the relative position of the rod 81 with respect to the base 80. Balance spring 93 and spring adjustment nut 95 interposed between the base 80 and the lower stabilizer block.
Is done by adjusting. The position of the reaction finger 85 for retracting the electrode 92 provided on the yoke 84 so as not to interfere with the work W is adjusted by the adjusting nut 97 provided on the base 80.

If the above-mentioned mechanism for moving the electrodes 91 and 92 to the facing position where they face each other and the retracted position where they do not interfere with the work W is provided, the spot welding gun is moved to the entire position. A shift mechanism was provided.

Further, as another spot welding gun, there are JP-A-59-125281 and JP-A-60-9588.
As disclosed in the publication, a cylinder (hereinafter, referred to as a tilting cylinder) that tilts and moves the electrodes so that the electrodes are opposed to each other and a retracted position that does not interfere with the work, A cylinder provided with a cylinder (hereinafter, referred to as a proximity separation cylinder) for bringing the electrodes close to each other to pressurize or separate the work is also known.

In the case of welding, in the case of welding, the electrodes are made to face each other by a tilting cylinder from a retracted position where they do not interfere with the work, and then the work is pressed by being brought close by a pressure cylinder. After the welding is completed, the electrodes are separated by the pressure cylinder, and the tilting cylinder tilts the electrode to one side with respect to the other electrode and retracts it so as not to interfere with the work.

[0010]

In the spot welding gun shown in FIGS. 9 and 10, the cylinder 83 and the yoke 84 can swing so as to incline with respect to the base 80 about the pivot 82. The angle that can be formed is small, and there is a problem that it is difficult to reliably retract the work W so that it does not interfere with the work W. Also, the retracted position is set by the adjustment bolt.
The position of the reaction finger 85 has to be adjusted by adjusting 97 with a tool or the like, which is difficult and time-consuming. Further, similarly, the adjustment of the positioning of the electrode with respect to the work also requires adjustment because the spring adjustment nut 95 is adjusted with a tool or the like, which is a problem.

In the spot welding guns disclosed in JP-A-59-125281 and JP-A-60-9588, the opposed positions where the electrodes are opposed to each other by the tilting cylinder and the retracted position where the electrodes do not interfere with each other. There is a problem that the two steps of the movement of inclining so as to raise and lower and the movement of bringing the electrodes into and out of contact with each other by the approaching and separating cylinder increase the time required to perform welding on the work. there were. Further, since the tilting cylinder and the close-spaced cylinder are separately provided, the problem that the cost increases due to the increase in the number of driving parts such as cylinders and valves, the control of each cylinder becomes complicated, and the equipment becomes large. There was such a problem.

The present invention has been made in view of the above problems, and the electrodes are made to approach and face each other along a rotation locus about the axis of a cylinder for driving the electrodes to approach and separate from each other, and are retracted as they are separated. Can be
Therefore, it is an object of the present invention to provide a spot welding gun capable of shortening the welding time. Another object of the present invention is to provide a spot welding gun capable of reliably retracting the electrode so as not to interfere with the work, and thus easily setting the work. A further object of the invention is
It is to simplify the structure of the spot welding gun and downsize it, and also, because it requires less equipment and facilitates its control.

[0013]

In order to achieve the above object, a spot welding gun according to the present invention comprises a pair of electrodes,
In a spot welding gun that includes a cylinder that drives the electrodes to move closer to and away from each other, one electrode is provided offset from the axis of the piston rod of the cylinder, and the electrodes are brought close to each other. And a rotating mechanism for rotating the piston rod so as to cancel the opposed state when they are opposed to each other and are separated from each other.

According to a second aspect of the present invention, in order to achieve the above object, in the spot welding gun according to the first aspect, the rotating mechanism is constituted by a cam groove and a cam follower provided in the cylinder and the piston rod. It is a feature.

According to a third aspect of the present invention, in order to achieve the above object, in the spot welding gun according to the first aspect, the rotating mechanism is attached to the piston of the cylinder and is provided with the piston by a working fluid supplied. It is characterized by being constituted by a rotating vane.

[0016]

Since the spot welding gun according to the present invention is configured as described in claim 1, when the electrodes are driven so as to approach each other by the cylinder for welding the work, the piston rod is rotated, The electrodes move about the axis of the piston rod, and oppose each other to clamp and press the work. When welding is completed and the electrodes are driven to separate from each other by the cylinder, the piston rod is rotated, the electrode moves around the axis of the piston rod, and the electrode is released so that it does not interfere with the work and interferes with the work. .

According to the second aspect of the invention, the electrodes are brought close to and opposite to each other along the rotation locus about the axis of the piston rod according to the cam groove engaged by the cam follower. , Retreat with separation.

According to the third aspect of the invention, the piston rod is rotated together with the vane by the working fluid supplied to extend and retract the piston of the cylinder.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the spot welding gun according to the present invention will be described below with reference to FIGS. The same reference numerals in the drawings denote the same or corresponding parts. The spot welding gun of the present invention generally comprises a pair of electrodes 1 and 2 for holding and pressing the work W, and a cylinder 3 for driving the electrodes 1 and 2 close to and away from each other. Cylinder 3 is
It is formed inside the equalizing block 4.

The equalizing block 4 is a bracket
The equalizing rod 7 mounted by the nut 6 is inserted into the 5 so that the bracket 5 can be moved. A gun head 9 is provided on the equalizing block 4 via an insulating material 8, and an electrode adapter 10 for supporting the electrode 2 is attached to the tip of the gun head 9. The bracket 5 is formed with a hole 5a through which the electrode adapter 10 can be inserted.

The cylinder 3 formed in the equalizing block 4 is fitted with a piston rod 12 via a bush 11. Cylinder 3 has port holes 13 and 14 at both ends.
Is formed, and the piston rod 12 is driven in the extension direction (upward in the drawing) and the retraction direction (downward in the drawing). A gun head 15 is attached to one end of the piston rod 12. The gun head 15 is provided with an electrode 1 offset from the axis of the piston rod 12 so as to face the electrode 2 provided at the tip of the electrode adapter 10 when the piston rod 12 is driven to retract. .

In the cylinder 3 and the piston rod 12,
A rotating mechanism 20 is provided for rotating the piston rod 12 so that the electrodes 1 and 2 face each other when they are close to each other and the facing state is released when they are separated from each other. Rotation mechanism 20
Is constituted by a cam groove 21 and a cam follower 22, and in the embodiment shown in FIG. 1, the cam groove 21 is formed on the peripheral surface of the piston rod 12, and the piston rod 12 of the equalizing block 4 is inserted. A cam follower 22 is provided on the inner peripheral surface of the cam follower 22. The cam groove 21 rotates the piston rod 12 so as to face the electrode 2 before the electrode 1 comes into contact with the work W by retracting the piston rod 12, and the piston rod 12 is extended so that the electrode 1 moves from the work W. Piston rod to release the facing condition after leaving
12 is formed so as to rotate. Both ends of the cam groove 21 are formed to have a length extending from a position where the electrodes 1 and 2 can clamp and press the work to a position where the electrode 1 can be sufficiently separated so as not to interfere with the work W. That is, the interval in the circumferential direction with respect to the piston rod 12, that is, the position of the electrode 1 facing the electrode 2 and the position retracted from the electrode 2 is formed to be deviated by 90 °.

The rotating mechanism 20 is not limited to this embodiment, and as shown in FIG.
The cam groove 21 on the inner peripheral surface where the piston rod 12 of
And the cam follower 22 can be provided on the piston rod 12.

The operation of the spot welding gun constructed as shown in FIG. 1 will be described. In the spot welding gun of the present invention in this embodiment, the bracket 5 is attached to an arm or the like (not shown) of a welding robot,
The work W is moved to a predetermined welding point. Before welding is started, the spot welding gun is supplied with working fluid such as compressed air from the port hole 13 into the cylinder 3 and the piston rod 12
Is being driven for extension. At this time, the electrode 1 which is provided eccentrically with respect to the axis of the piston rod 12 via the gun head 15 is separated from the work by the cam groove 21 engaged with the cam follower 22 and is in a position facing the electrode 2. From 90 °
In the state where the work W is rotated and displaced, the work W is retracted so as not to interfere with the work W. Further, the equalizing block 4 inserted into the equalizing rod 7 is located away from the work W, and the electrode 2 is also located away from the work W as well.

When welding the work W, the port hole 14
Supply the working fluid to the cylinder 3 from the piston rod 12
Drive retraction. At this time, the piston rod 12 is rotated by the formed cam groove 21 being guided by the cam follower 22, and the electrode 1 faces the electrode 2 along a rotation locus about the axis of the piston rod 12. And then comes into contact with the work W. When the piston rod 12 is further driven to extend, the equalizing block 4 slides toward the work W while being guided by the equalizing rod 7, and the electrode 2 contacts the work W. The work W is welded by being supplied with an electric current while being sandwiched and pressed by both electrodes 1 and 2.

Next, another embodiment of the spot welding gun according to the present invention will be described with reference to FIGS.
Note that the same reference numerals are given to the same or corresponding portions as those in the above-described embodiment, and the description thereof will be omitted.

The point that the spot welding gun in this embodiment is different from the above-mentioned embodiments is that the electrodes 1 and 2 are opposed to each other when they are close to each other and the opposed state is released when they are separated from each other. Rotation mechanism 40 for rotating 42
It is in. The rotating mechanism 40 in this embodiment has the vanes 44 attached to the pistons 43 of the piston rods 42 and ejects a working fluid such as compressed air for driving the piston rods 42 to extend and retract to the vanes 44. The piston cylinder 42 is rotated together with 44. The spot welding gun in this embodiment includes a rotating mechanism 40 and a restricting means 45 for restricting the rotation of the piston rod 42.

A piston rod 42 is fitted and inserted in the cylinder 3 formed in the equalizing block 4, and a cushion material 50 is provided on the upper end surface in the drawing inside thereof. As shown in the perspective view of FIG. 4 and the bottom view of FIG.
The piston 43 has a closed portion 52 having a notch 51 on the upper side and a vane 44 on the lower side. A groove 53 for attaching a ring-shaped seal member 54 made of an elastic body or metal and a wear ring 55 (see FIG. 3) is formed on the outer peripheral surface of the piston. In the case of this embodiment as well, similar to the previous embodiment, the angle between the position of the electrode 1 facing the electrode 2 and the position of withdrawing from the electrode 2 is deviated by 90 °. As described above, the closing portion 52 is formed over three quarters of the outer circumference of the piston 43, and the notch 51 is formed over one quarter of the outer circumference of the piston 43. In FIG. 3, reference numeral 56 indicates a seal member, and reference numeral 57 indicates a rod bearing.

The port hole 13 formed in the equalizing block 4 includes an opening 60 formed at the lowermost portion of the cylinder 3 in the drawing and a closing portion 52 of the piston 43 when the electrodes 1 and 2 clamp and press the work W. Is continuous with the opening 61 formed in the inner wall surface of the cylinder 3 where is located. Also, the port hole 14
Is an opening 62 formed on the inner wall surface of the cylinder 3 in which a closing portion 52 having a notch 51 of the piston 43 is located when the electrodes 1 and 2 are separated from each other and the piston 43 comes into contact with the cushion material 50, and the piston 43. The vanes 44 are continuous with the opening 63 formed in the inner wall surface of the cylinder 3. Aperture 61 and Aperture 63
Is for ejecting a working fluid such as compressed air to the vane 44. As shown in FIG.
It is formed so as to hit at a right angle with respect to, or is formed so as to hit the outer peripheral end of the vane 44.

As the restricting means 45 for restricting the rotation of the piston rod 42, as shown in FIGS. 3 and 7, a pin 65 penetrating the piston rod 42 and an upper surface of the equalizing block 4 are provided. It is composed of the formed stopper portion 66. In addition, equalizing block 4
A compression spring 67 is interposed between the equalizing block 4 and the bracket 5 when its own weight is large.

The operation of the spot welding gun of the present invention constructed as described above will be described below.
As shown in FIG. 3, when the working fluid is supplied into the cylinder 3 from the openings 62 and 63 through the port hole 14, the piston rod 42 is driven to retract, and the work W is clamped by the electrodes 1 and 2 facing each other. Welding is performed under pressure. When the welding is completed, the supply of the working fluid is switched from the port hole 14 to the port hole 13. At this time, since the opening 61 is closed by the closing portion 52 of the piston 43, the working fluid is supplied into the cylinder 3 through the opening 60 and extends without rotating the piston rod 43, so that the electrode 1 can be extended. It is separated from the work W while facing the electrode 2. Equalizing block 4
Is moved away from the work W while being guided by the inserted equalizing rod 7, and the electrode 2 is also separated from the work W.

The piston rod 43 is driven to extend to open the opening 61.
When the vane 44 of the piston 43 reaches the position of, the working fluid is ejected from the closed opening 61 to the vane 44, and the piston rod 43 extends and rotates as shown in FIG. 8A. The electrode 1 moves to move along a rotation locus around the axis of the piston rod 42 and retracts so as not to interfere with the work W. Dashed line in FIG. 7 and (b) in FIG.
As shown in, the pin 65 provided on the piston rod 43 comes into contact with the stopper portion 66, so that the piston rod 43
The rotation of 43 is restricted. At this time, the closing portion 52 of the piston 43 closes the opening 62.

When welding is started by driving the welding robot to move to the next welding point or the like, the working fluid is supplied from the port hole 14, but as shown in FIG.
Since the opening 62 is closed by the closing portion 52 of the piston 43, the working fluid is ejected to the vane 44 through the opening 63 to rotate the piston rod 42, and the pin 65 provided on the piston rod 43 is released. It contacts the stopper member 66 and restricts the rotation of the piston rod 43, and the electrode 1 moves along a rotation locus around the axis of the piston rod 42 and faces the electrode 2. When the piston rod 42 rotates as shown in FIG. 8C, the notch 51 formed in the closing portion 52 of the piston 43 is located in the opening 62, and the working fluid is also supplied from this opening 62. The piston rod 42 is driven to retract and the electrode
1 contacts the welding point of the work W, and further retracting of the piston rod 42 causes the equalizing block 4 to slide toward the work W while being guided by the equalizing rod 7, and the electrode 2 contacts the work W. And
The electrodes 1 and 2 are welded by applying an electric current while the work W is clamped and pressed.

[0034]

According to the invention described in claims 1 to 3, one of the electrodes is provided so as to be deviated from the axis of the piston rod of the cylinder, and the electrodes are opposed to each other and are separated from each other when the electrodes approach each other. By providing the rotating mechanism for rotating the piston rod so as to release the facing state at the time, the electrodes can be brought close to each other and face each other, and can be retracted as they are separated from each other, thereby shortening the welding time. be able to

Further, according to the present invention, the electrode can be separated and moved along the rotation locus around the axis of the piston rod so as not to interfere with the work, and the work can be reliably retracted. It can be set easily.

Further, according to the present invention, the structure of the spot welding gun can be simplified and downsized, and the peripheral accessories and the like can be reduced, and the control thereof can be facilitated.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing an embodiment of a spot welding gun according to the present invention.

FIG. 2 is a partial cross-sectional view showing a modified example of the spot welding gun of FIG.

FIG. 3 is a partial cross-sectional view showing another embodiment of the spot welding gun according to the present invention.

FIG. 4 is a perspective view of the piston shown in FIG.

FIG. 5 is a bottom view of FIG. 4;

FIG. 6 is a schematic cross-sectional view showing a vane provided in a piston and an opening for ejecting a working fluid into the vane.

FIG. 7 is a schematic plan view showing a rotation restricting means of a piston rod.

FIG. 8 is a diagram illustrating a process in which the cylinders are extendedly driven to be separated from each other when the electrodes are opposed to each other, retracted, and again opposed to each other by a partial cross-sectional view and a plan view showing a direction of a gun head provided with electrodes. is there.

FIG. 9 is a view showing an example of a spot welding gun which has been conventionally used.

FIG. 10 is a diagram showing a state in which the spot welding gun of FIG. 9 is retracted so as not to interfere with a work.

[Description of sign]

 1 electrode 2 electrode 3 cylinder 12 piston 20 rotation mechanism 21 cam groove 22 cam follower 40 rotation mechanism 42 piston rod 43 piston 44 vane 45 rotation restricting means

Claims (3)

[Claims] 1. A spot welding gun comprising a pair of electrodes and a cylinder for driving the electrodes in close proximity to each other, wherein a work is clamped and pressed by both electrodes, and one electrode is displaced with respect to the axis of the piston rod of the cylinder. The spot welding gun is characterized in that a rotating mechanism is provided to rotate the piston rod so that the electrodes are opposed to each other when the electrodes are close to each other and the opposed state is released when the electrodes are separated from each other. 2. The spot welding gun according to claim 1, wherein the rotating mechanism comprises a cam groove and a cam follower provided in a cylinder and a piston rod. 3. The spot welding gun according to claim 1, wherein the rotating mechanism is constituted by a vane that is attached to a piston of the cylinder and rotates together with the piston by a supplied working fluid.