JPS5827029B2 - welding gun - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a welding gun, in particular a method in which the outer periphery of an electrode tip that can be moved forward and backward is covered with a cylindrical pressing tip, and the tip of the electrode tip is removed inside the pressing tip. The present invention provides a welding gun provided with a ring-shaped pressing tip cleaning member having an insulating layer interposed therebetween.

In recent years, steel plates used in automobiles have been made thinner to reduce weight, and for this reason, there is a tendency for high-strength steel to be used for important safety parts.

On the other hand, when spot welding is performed, in the case of high-tensile steel, the stress of the material itself and the springback caused by press forming are strong, so it is necessary to use one clamp for four to five welding points as in the past. This method cannot apply sufficient pressure and cannot guarantee good welding, so the area around each welding point must be clamped.

Incidentally, spot welding on an automobile manufacturing line is normally carried out by placing a large number of welding guns in parallel in a relatively narrow space to perform spot welding at a large number of points at the same time.

In addition, spot welding is also carried out by inserting an electrode tip into a narrow valley-shaped space formed by a press.

Therefore, when clamping the periphery of each spot welding point, it must be done in a relatively narrow and limited space, and it is necessary to develop an appropriate ramp means for this purpose.

The present invention has been made in view of the above circumstances, and provides a pressing tip as a clamping means coaxially around an electrode tip, and the pressing tip is commonly driven by a cylinder that drives the electrode tip forward and backward. It has a function to reliably clamp the area around the spot welding point, and it only needs to be about the same size as a normal one, so it can be used easily even in a narrow space. To provide a welding gun which is equipped with a slidable ring-shaped cleaning member and can automatically sweep away spatter adhering to the inner wall of a suppression tip during welding work.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 9.

In the figure, 1 is a cylinder, and this cylinder 1 has inner and outer actuating bodies 2 and 3 that are coaxially provided and move forward and backward independently of each other.

To explain this cylinder 1 in more detail, a plug body 5 is tightly fitted into the rear end opening of a cylindrical cylinder main body 4, and a cylinder chamber 7 is tightly plugged with a partition wall 6 integrally provided in the middle part. A cylinder chamber 8 with one end open is formed.

Then, the piston 9 is slidably fitted into the cylinder chamber T, and the plug body 5 is provided with a port P that communicates with the chamber 7a formed between the plug body 5 and the piston 9. A port P2 communicating with a chamber 7b formed between the piston 9 and the piston 9 is provided in the partition wall 6.

The outer actuating body 3 has slit-shaped openings 10.10 along the axis symmetrically on both sides from the tip to the middle of the cylindrical body.
In addition, an end wall 11 is provided at the rear end of the cylindrical body.

The inner working body 2 has an end wall 13 at the rear end of the cylindrical part 12,
A small diameter round rod portion 14 extends from the axial center of the end wall 13.
It is something that is distracting.

The outer actuating body 3 is fitted with its rear end into the cylinder chamber 8 of the cylinder body 4 coaxially from its tip opening, and with its outer circumferential surface slidingly in contact with the inner circumferential surface of the cylinder body 4 so that it can move forward and backward. There is.

The inner actuating body 2 is fitted into the rear end of the outer actuating body 3 coaxially with its cylindrical portion 12, with its outer circumferential surface slidingly contacting the inner circumferential surface of the outer actuating body 3 so that it can move forward and backward, and its rod The portion 14 is passed through the end wall 11 of the outer actuating body 3 and the axial center portion of the partition wall 6, and the small diameter screw portion at the tip thereof is attached to the piston 9 with a nut 15.

A port P3 communicating with the chamber 8a formed between the partition wall body 6 and the end wall 11 of the outer actuating body 3 is provided in the partition wall body 6, and a port P3 is provided in the partition wall body 6 and the end wall inside the outer actuating body 3. 11
A passage 17 is provided in the rod portion 14 of the inner actuating body 2 to communicate with the chamber 16 formed between the end wall 13 of the cylindrical portion 12 of the inner actuating body 2.

In addition, a retaining ring 1 is attached to the tip opening of the cylinder body 4.
A cap nut 19 is screwed together via 8.

As shown in FIG. 2, the retaining ring 18 has a protrusion 1 on its inner peripheral edge that fits into the openings 10, 10 of the outer operating body 3.
8a.

Further, a key groove 2 is formed on the outer circumferential surface of the rear end of the outer operating body 3 and on the inner circumferential surface of the open end side of the cylinder body 4 in parallel with the axis.
A locking key 21 that fits into the lock is provided protrudingly.

A cylindrical pressing tip 23 made of a non-magnetic material such as stainless steel or gun metal is fitted onto the tip of the outer operating body 3 and fixed with a bolt 24.

On the other hand, the press tip 23 formed into a cylindrical shape encloses an electrode tip 28 whose entire outer periphery except for the tip is covered with an insulating layer 50, and furthermore, a ring-shaped cleaning member is attached to the outer periphery of the insulating layer 50. 51 is attached so as to be in sliding contact with the inner circumferential wall surface of the pressing tip 23.

Therefore, the relative movement of the pressing tip 23 and the electrode tip 28 in the axial direction allows the pressing tip cleaning member 51 to slide by a predetermined width on the distal end side of the pressing tip 23, as shown in FIG. 7 during welding. As shown in FIG. 8, the spatter 52 attached to the inner peripheral wall surface of the suppression chip 23 can be automatically swept outward.

In addition, a spring unit 2 is provided at the tip of the inner operating body 2.
5. The electrode tip 28 is attached via the connecting member 26 and the power receiving member 27.

The spring unit 25 has a rod 30 having a collar 29 at one end, and a retaining pin 31 at the other end, and a plurality of disc springs 32 are arranged between the collar 29 and the retaining pin 31 in a required number of units with different orientations. It is externally fitted onto the rod 30.

As shown in FIG. 6, the connecting member 26 has a large-diameter cylindrical body 34 and a small cylindrical body 35 coaxially protruding from both sides of a substantially rectangular collar 33 provided at an intermediate portion. A recess 36 is formed in the end face of the plate.

As shown in FIG. 6, the power receiving member 27 has a cylindrical electrode holder 38 protruding from one end side of a rectangular plate-like power receiving terminal portion 37. A connecting hole 39 with a depth that spans the electrode holder 38 is bored in one end, and a groove 40 is provided extending from the other end to the connecting hole 39.

Further, an electrically insulating layer, for example, a synthetic resin plate 41, is applied to a local area around the side of the power receiving terminal portion 37.

Note that the electrode tip 28 is screwed onto the tip of the electrode holder 38.

As shown in FIG. 1, the connecting member 26 is coaxially housed in the cylindrical portion 12 of the inner actuating body 29, and the spring unit 25 is coaxially accommodated in the cylindrical portion 12 with the collar 29 disposed inside. The large-diameter cylindrical body 34 is fitted into the disc spring 32 of the spring unit 25 so as to be movable forward and backward, and the pin 42 is fitted into the elongated hole 43 of the cylindrical part 12 to connect the spring unit 25.

The range of movement of the connecting member 26 relative to the inner operating body 2 is restricted by a long hole 43 into which the pin 42 is fitted.

Further, the rotation of the connecting member 26 is restricted by fitting the collar 33 into the openings 10, 10 of the outer operating body 3.

Then, the connecting member 26 is fitted into the connection hole 39 of the power receiving member 27 by covering the small diameter cylindrical body 35 on the outer periphery of the small diameter cylindrical body 35 and fitting it into the connection hole 39 of the power receiving member 27.
They are connected by tightening a tightening bolt 45 which is threaded to narrow the width of the groove 40.

Electrode holder 38 portion of power receiving member 27 and its electrode holder 3
The electrode tip 28 attached to the tip of the electrode tip 8 is housed coaxially within the outer operating body 3 with an insulating space provided around it.

The power receiving terminal 37 portion of the power receiving member 27 projects to the outside through one opening 10 of the outer operating body 3 and is connected to the power supply cable 46 .

With such a configuration, for example, as shown in FIG.
Each port P1 of cylinder 1. P2. Change the hydraulic control circuit to the switching valve for P3 ■1. (2) By connecting through 2, the inner and outer actuating bodies 2 and 3 can be moved forward and backward.

That is, when hydraulic pressure is applied to the chamber 8a from the circuit through the port P3, the outer actuating body 3 is pushed forward by the end wall 11,
This allows the pressing tip 23 to move forward.

Furthermore, when hydraulic pressure is applied to the chamber 7a through the port P1, the inner working body 2 moves forward through the piston 9, and the electrode tip 2 moves forward through the piston 9.
8 can be advanced.

In addition, in each of these forward motions, the chamber 7b is kept in a free flow state through the port P2 to the tank in the hydraulic control circuit.

On the other hand, switching valve v1. (2) Switch the chamber 7a8a to port P1. in free flow to the tank via P2;
When hydraulic pressure is applied from the circuit to the chamber 7b through the port P2, a pressing force acts on the piston 9, allowing the inner and outer actuating bodies 2 and 3 to retreat.

Therefore, as shown in FIG.
If welding is performed by holding the objects A and B from the back side using the back-up member 48 and the back-up member 48, the objects A and B are firmly clamped by the pushed forward press tip 23 and the backup member 48 during welding. Because you can
The object to be welded A.

Good welding results can be reliably obtained even when B has large internal stress and springback, such as high-tensile steel.

Note that even if the electrode tip 28 is fused to the object A to be welded and the electrode tip 28 does not retreat after welding is completed, the pressing tip 23 retreats first, which causes the nut of the electrode tip 28 to 28a, and the return force of the suppressing tip 23 is applied to the electrode tip 28. In other words, the return forces of the inner and outer actuators 2 and 3 are applied at the same time, so that the electrode tip 28 can be reliably removed from the workpiece A. Can be separated.

Note that if the suppression chip 23 is made of a non-magnetic material as in the above embodiment, it will not be affected by the adverse effects of induced heat generation.

Note that the outer operating body 3 is split into two at the opening 10 at its tip, so that the effect of induced heat generation is small.
Although magnetic materials may be used, it is preferable to use non-magnetic materials.

Further, in the embodiment described above, a passage 17 is provided in the inner working body 2, and fluid pressurization is simultaneously applied to the two chambers 7b and 16 in the cylinder 1 that communicate with each other via the passage 17. This is to drive the inner and outer actuating bodies 2, 3 backward substantially simultaneously, and the passage 17 can be omitted depending on the case.

For example, by reducing the distance a (see FIG. 1) between the end wall 13 of the inner actuating body 2 and the end wall 11 of the outer actuating body 3, the end wall 13 is moved outward after the inner actuating body 2 has retreated by a predetermined stroke. If it is brought into contact with the end wall 11 of the actuating body 3, the inner and outer actuating bodies 2.3 can be retracted in conjunction with each other by the mechanical locking operation thereof, so that the passage 17 can be omitted.

By the way, in spot welding, when a nugget is generated on the workpiece, a phenomenon occurs in which the electrode tip abutting portion of the workpiece becomes slightly depressed.

In this case, if hydraulic control, ie, non-compressible fluid control, is used as in the above embodiment, it is generally difficult to cause the electrode tip 28 to instantaneously protrude into the recess.

However, if the electrode tip 28 is elastically biased in the projecting direction by the disk spring 32 of the spring unit 25 as in the embodiment described above, the corresponding instantaneous projecting action can be reliably obtained.

Note that if the control fluid for the cylinder 1 is a compressed fluid such as air, an instantaneous ejecting action can be obtained by pressurization, so that the spring structure as in the previous embodiment can be omitted.

In addition, in the embodiment described above, slit-shaped openings 10 were formed on both sides of the outer operating body 3, but these openings 10
It suffices if the opening is provided on at least one side of the actuating body 3 to draw out the information.

As described in detail above, according to the present invention, a suppression chip is provided coaxially around an electrode chip, and the suppression chip is commonly driven by a cylinder for driving the electrode chip, so that the structure is simple. It does not become particularly large, and therefore, even when welding in several places at once in a narrow space, the area around each welding point can be reliably clamped.

In addition, since a cleaning member that slides into contact with the inner peripheral wall surface of the suppression chip is attached to the electrode chip covered by the pressing tip, spatter attached to the inner wall surface of the suppression chip can be automatically swept away. It is extremely convenient.

[Brief explanation of drawings]

Figures 1 to 9 show one embodiment of the present invention.
The figure is a sectional view showing the overall structure, and FIGS. 2, 3, and 4 are taken along line nn of FIG. 1, respectively. 1-III, a sectional view taken along the line IV-IV, FIG. 5 is a partially cutaway side sectional view of FIG. 1, FIG. 6 is a perspective view showing the assembled state of the main parts, and FIGS. FIG. 9 is a side vertical cross-sectional view of the welding gun of the present invention in use, showing the sweeping action. 1...Cylinder, 2...Inner operating rod, 3...Outer operating rod, 23...
Pressing chip, 27...Power receiving member, 28...
...Electrode chip, 37...Power receiving terminal, 50...
...Insulating layer, 51...Press tip cleaning member.

Claims (1)

[Claims] 1. Among the coaxially arranged units that move forward and backward independently of each other,
a cylinder having an outer actuating body; attached to the tip of the inner actuating body in an electrically insulated manner;
a power receiving member disposed within the outer operating body; a ring-shaped pressing tip cleaning member attached to the tip of the power receiving member with an insulating layer interposed in the portion excluding the tip; and a ring-shaped pressing tip cleaning member attached to the outer periphery of the insulating layer. a cylindrical pressing tip attached to the tip of the outer operating body so as to be in sliding contact with the outer periphery of the cleaning member to cover the electrode tip; A welding gun characterized by comprising a power receiving terminal projecting outward through an opening along an axis formed in an outer operating body.