SK169299A3 - Seam welding head - Google Patents

Abstract

Seam welding head has on its fixed part (1) the first contact track (2) on the rotating part (3) the second contact track (4) and between contact tracks (2, 4) are contact elements (5). In the contact surfaces of the contact elements (5) with contact tracks (2, 4) is pressure bias created by spring (9). The contact tracks (2, 4) has the form of coaxial rotating, profitably conic surfaces and contact elements (5) have, profitably, conical surfaces, small barrel or rolling-pin. The fixed part (1), rotating part (3) and contact elements (5) are made from copper alloy. There are spaces between the contact tracks (2, 4) for flowing of the cooling fluid. The contact elements (5) can be hollow and stored on the pins (7) of the dowel crown (6).

Description

Technical field

The invention relates to seam welding heads used in welding machines for electrical resistance seam welding, which serve to transfer electrical current from a fixed part to a rotating electrode.

BACKGROUND OF THE INVENTION

A number of principles and design solutions for seam welding heads are known. In the case of seam welding heads, it is particularly necessary to ensure the transmission of a high-intensity direct, pulsating or alternating current, in the order of tens of kA, from the fixed part of the head to the rotating electrode. In addition, it is necessary to provide a sufficiently rigid rotary bearing of the electrode allowing the application of a contact force between the electrodes of the order of magnitude in kN, cooling the electrode by the flow of coolant, usually water, cooling the head itself at transient electrical resistors and driving one or both heads used on the welding machine. .

The simplest known construction of the seam welding head consists of a fixed part in the form of an open angular container, in the side walls of which sliding bearings receive a rotating part carrying a disc electrode in the middle, the electrode wading in water which is fixed as a container. The electric current passes through the sliding bearings of the rotating part. The disadvantage of this solution is its usability only in the lower position without drive, difficult operation and low bearing life.

It is known to provide a seam welding head with a disc electrode placed in an abrupt manner at the front end of the rotary part housed in a long cylindrical plain bearing and the current is guided by the plain bearing itself. The cooling water supply to the rotating part cavity and electrode is in the rear axis of rotation. The disadvantage is difficult operation, as with all solutions

- 2 with plain bearings, the need for frequent lubrication and low bearing life due to the occurrence of ultimate friction despite the use of special copper alloys.

It is known to provide a seam welding head with an overhung electrode at the front end of the rotary part, which is mounted in a large tapered plain bearing of the fixed part. The rotary part is driven by a worm wheel through the tongue, which is fixed in the fixed part in ball bearings. A spring is supported on the rear ball bearing, the rear end of which bears on the nut screwed on the rotary part. In a non-driven variant of such a seam welding head, the front end of the spring is supported on an axial sliding bearing. The spring pulls the rotating part into the tapered plain bearing by a force that can be controlled by changing the compression of the spring by means of a nut. The cavity of the rotating part and the electrode with the cooling water inlet and outlet in the rear rotation axis is cooled. Also, the cavity in the fixed portion formed around the cone of the tapered plain bearing is cooled, with a water inlet over the shoulder, by means of which the seam welding head is attached to the welding machine and with which a current is also supplied. The cooling water is discharged from the fixed portion at the location of the cavity formed around the plain bearing cone. As a separate component, the conical plain bearing shell is made of a special copper alloy, as well as the rotary part, inserted and sealed in the fixed part. The current is fed from the fixed part to the rotating part by a plain tapered roller bearing. The disadvantage is the heavy running of the rotating part due to limit friction, the necessity of very frequent lubrication with special grease and low durability of the plain bearing.

It is also known to provide a seam welding head in which the rotating part is housed in insulated plain bearings and the electric current is fed to the rotating part through mercury in which the discs are wading.

It is also known to provide a seam welding head in which the rotating part is housed in needle bearings and the current is fed to the electrode by mercury in which the shaft of the rotating part is waded directly.

The disadvantage of seam welding seams with a mercury current passage is that they cannot be properly sealed, resulting in the release of toxic mercury vapors, which is environmentally unacceptable.

It is known to provide a seam welding head, the rotating part of which is housed in ball or sliding bearings, and the current is fed to the electrode by sliding contacts made as a slip ring, over which surface brushes of wires or strips made of special copper alloy with high content silver. The disadvantage is the necessity of very frequent lubrication of sliding contacts and their high price.

The main disadvantage of the known solutions, with the exception of mercury heads, is that the current supply is in principle always sliding contact, whether it is a cylindrical or tapered plain bearing, or as a thrust bearing, or as a slip ring with brushes. The passage of the current requires a clean metal contact of the shaft with the bearing shell, respectively the brush and the collector ring, so that the shaft to the shell or the brush to the collector ring must be pressed down. The pressing force increases the sliding friction, which makes it more difficult to rotate the rotating part and causes faster wear of the sliding pair. To prevent seizure of the sliding pair, frictional friction at the interface of the dry and liquid friction must be ensured, which increases the transient electrical resistance and thus the energy loss, heating and requires frequent regreasing even when using a special grease. Limiting friction is also the cause of rapid wear and low durability of sliding contact parts.

SUMMARY OF THE INVENTION

The seam welding head according to the invention is substantially reduced or eliminated by virtue of its first contact path on its fixed part, the second contact path on the rotating part carrying the disk electrode and the contact bodies between the contact paths. In the contact surfaces of the contact bodies with the contact paths, the pressure bias is created by a spring.

The contact paths are in the form of coaxial rotating, preferably conical, surfaces and the contact bodies are preferably in the form of cones, spheres or rollers. The fixed part, the rotating part and the contact bodies are of copper-containing alloys. Between the contact paths and the contact bodies there are gaps for the coolant flow, which ensures heat dissipation directly from the place of its generation when the electric current passes. The contact bodies can be hollow and mounted on the crown pins to provide guidance and equal spacing, greater flexibility and larger contact pads with contact paths and thereby better electrical current passage. The spring is a thrust, preferably a helical cylindrical, and is inserted between the fixed portion and the rear bearing. The spring may also be screwed, interposed between the fixed part insert and the tensioning device. The spring may also have the shape of two parallel arms formed by cutting the bracket in its left portion.

The main advantage of the seam welding head according to the invention, compared to the previously known sliding contact solutions, is a much easier rotation of the disc electrode comparable only to heads using toxic mercury, furthermore a long service life and considerably lower operation and maintenance requirements with substantially less electrical resistance and thus less energy losses, less heating and less cooling. The advantage is also a lower price compared to heads whose sliding contact is made of an alloy containing up to 80% silver. Due to the low rolling resistance, it is advantageous to use in the welding machine of the installed pair of heads only one seam welding head according to the invention with drive and the other non-driven even in cases where using previously known seam welding head solutions moreover, the differential had to be connected.

BRIEF DESCRIPTION OF THE DRAWINGS

Four embodiments of a seam welding head according to the invention are shown. Figure 1 shows a longitudinal section of the seam welding

- 5 heads on the left with the main rolling contact and on the right with the secondary rolling contact serving as the rear bearing. 2 shows a partial longitudinal section of a seam welding head having a rolling contact on the left and a rear tapered roller bearing on the right. Figure 3 shows the seam welding head in cross-section along the line A - A shown in Figure 2; Figure 4 shows a longitudinal section of the seam welding head in inverse configuration, without a shaft, with contact bodies in the form of rollers. Figure 5 shows a longitudinal section of the seam welding head in an inverse configuration, without a shaft, with an electrode transverse and with contact bodies in the form of rollers. Figure 6 shows the seam welding head in cross-section along line B-B and Figure 7 in longitudinal section through plane C-C. The sectional planes B - B and C - C are shown in Figure 5.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

A first specific embodiment of the invention shown in Figure 1 is a seam welding head, in the left part of which is a main rolling contact consisting of a first contact path 2 on the fixed part 1, a second contact path 4 on the rotary part 3 and contact bodies 5 interposed contact tracks 2, 4, guided by pins 7 of crown 6 and secured with washers and nuts. In the rotary part 3, a tube 8 is pressed into the axial bore. In the fixed part 1, a compression helical cylindrical spring 9 is inserted, which is supported by its left end over the insulating washers against the fixed part 1. The middle seal 10 is mounted between the insulating washers. its right end bears on the washer and the rear bearing 12, which is a secondary rolling contact consisting of the same parts as the main rolling contact. The rear bearing 12 is supported by the nut 11. From the right side, the fixed part 1 is closed by the rear lid 14, in which the rear seal 13 is mounted. The front seal 15 is mounted in the front lid 16.

An electrode 17 is attached to the front end of the rotary part 3. In the fixed part 1 there is an inlet opening 20 and an outlet opening 24 for coolant. The central seal 10 divides the interior of the fixed part 1 into a front space 23 and a rear space 21. In the electrode 17 there is a cavity 22 for cooling it. The lower surface of the fixed part 1 serves for fastening to the welding machine and supplying electric current.

Example 2

A second particular example of the construction of the seam welding head according to the invention is shown in Figures 2 and 3. In the left part of the seam welding head shown in Fig. 2 is a rolling contact consisting of a first contact path 2 in a solid part 1 casting, second contact path 4 on a rotating part 3 and contact bodies 5 interposed between the contact tracks 2, 4, guided by pins 7 of the crown 6 and secured with washers and nuts. From the right side is to the fixed part

An inserted compression helical cylindrical spring 9 is supported by its left end against a fixed part 1. The right end is a spring 9 supported by a conventional steel tapered rear bearing 12 which is supported by a nut

II and imprinted on the spacer. The right side of the fixed part 1 is closed by the rear lid 14. The front seal 15 is mounted on the left side of the fixed part 1 and covered by the front lid 16. An electrode 17 is attached to the front conical end of the rotary part 3. 24 for coolant. The bottom surface of the cast part of the fixed part 1 serves for attachment to the welding machine and as a power supply. The interior space of the fixed part 1 is divided by a central seal 10 housed in a partition wall, into two parts, a rear space 21 on the right and a front space 23 on the left. These are interconnected by the axial bore of the rotary part 3, in which the tube 8 is pressed. To the right of the rear space 21 is a rear seal 13. Both the rear space 21 and the front space 23 are connected to the axial bore of the rotary part 3 by radial holes. In the electrode 17 there is a cavity 22 for cooling it.

- 7 Example 3

A third specific example of the construction of the invention, shown in Figure 4, is a seam welding head in an inverse arrangement without a shaft, on the left side of which a rolling contact consisting of a first contact track 2 on a two-piece fixed part 1 is formed; The two-piece fixed part 1 consists of a shoulder at the left end of the circular cross-section bracket 18 into which the insert is screwed. The electrode 17 is mounted on the rotating part 3, sealed to the fixed part 1 by the front seal 15. The spring 9 is mounted on the left in the insert of the fixed part 1 and on the right in the tensioning device 19 for adjusting the biasing. A tube 8 is molded in the axial bore of the bracket 18. Between the rigid insert 1 and the tube 8 there is a central seal 10 separating the rear space 21 and the front space 23. There is a cavity 22 in the electrode 17 to cool it. 14. In the bracket 18 is an inlet port 20 and an outlet port 24 for coolant. The surface of the bracket 18 serves for attachment to the welding machine and as a power supply.

Example 4

A fourth specific example of the construction of the seam welding head according to the invention is shown in Figures 5, 6 and 7. Again, this is an inverse arrangement without a shaft, but the electrode 17 is disposed transversely. In the left part, the circular cross-section bracket 18 is cut so that it has the shape of two parallel spring arms 9. At the end of the spring arms 9, two parts of the fixed part 1 are supported symmetrically with respect to the bracket axis 18. the contact track 4 in the rotary part 3 and the contact bodies 5 interposed between the contact tracks 2 and 4 form a rolling contact. Two parts of the fixed part 1 are attached to the arms of the spring 9 by the front

The bias of the spring arms 9 is adjustable by the tensioning device 19. In the bracket 18 there is an inlet opening 20 leading to the rear compartment 21 and an outlet opening 24 resulting from the front compartment 23.

In both pieces of the fixed part 1 there are openings which allow the coolant to flow from the rear space 21 through the gaps between the contact paths 2 and 4 and the contact bodies 5 into the front space 23. The electrode 17 is mounted on the rotating part 3 The two parts of the fixed part 1 have their openings separated from each other by the middle seal 10.

The seam welding heads according to the invention operate in such a way that the electrode 17 attached to the rotary part 3 rotates, with the contact bodies 5 rolling along the first contact path 2 and the second contact path 4.

In the contact surfaces of the contact paths 2 and 4 with the contact bodies 5, the pressure prestressing created by the spring 9 as well as the contact force applied at the weld site on the electrode 17 ensures a clean metallic contact and thus low transient electrical resistance when In the cases shown in Figures 1, 2 and 3, a compression spring 9 is used. The reaction of the spring 9 is captured by the rear bearing 12. In the case shown in Figure 4, a helical spring 9 is used which tightens the housing of the fixed part 1 as a screw. In the case shown in Figures 5, 6 and 7, a shaped spring 9 is used in the form of resilient arms, pressing together two pieces of the fixed part 1. The reaction to the contact force acting at the weld location on the electrode 17 engages the main rolling contact and the rear bearing in the case shown in Figures 4, 5, 6 and 7, the rolling contact itself. The heat generated at the weld site and the electrical contact passing through the rolling contact is removed by the cooling fluid which, in the case shown in Figures 1, 2 and 3, enters the fixed part 1 through the inlet 20, flows into the rear space 21. its axial bore and through the tube 8 to the walls of the cavity 22 in the electrode 17, drawing therefrom the heat generated at the weld site. The coolant continues to flow through the gap

9 between the outer wall of the tube 8 and the wall of the axial bore of the rotary part 3, through the radial holes and between the contact bodies 5 and the contact paths 2 and 4, thereby taking heat generated at the point of electric current passage through the roller contact into the front space 23 and flowing through the outlet 24 out of the fixed part 1. The lower surface of the fixed part 1 also serving as a power supply is a seam welding head attached to the welding machine. In the case of a driven seam welding head, the rotating part 3 is driven through the tongue at its rear end. In the case of a non-driven seam welding head, the rotating part 3 rotates freely.

In the case of the seam welding head shown in Figure 4, the coolant flows from the rear space 21 directly through the tube 8 to the cavity 22 in the electrode 17, further through the gaps between the contact bodies 5 and the contact paths 2 and 4 and from there to the front space 23.

In the case of the seam welding head shown in Figures 5, 6 and 7, coolant flows from the rear space 21 through openings in one half of the fixed part 1 to the gaps between the contact bodies 5 and the contact paths 2 and 4 and openings in the other half of the fixed part 1 into the front Space 23.

In the cases of Figures 4, 5, 6 and 7, the seam welding head is held in the welding machine by the surface of the bracket 18 with a circular cross section, which also serves as a power supply. The seam welding heads shown in Figures 4, 5, 6 and 7 are not driven.

Commercial water of usual quality can be used as a cooling liquid. To ensure a longer lifetime of the seam welding heads, it is preferable to use demineralized water, possibly with lubricating and antioxidant additives.

The seam welding heads according to the invention shown in Figures 1, 4, 5, 6 and 7 are intended in particular for the use of an alternating welding current. The seam welding head according to the invention shown in Figures 2 and 3 is intended, in particular, for the use of a direct welding current, where a conventional tapered roller bearing can be used as the rear bearing 12. For

- 10 if an alternating welding current is used, a non-magnetic bearing must be used in such a seamed welding head.

Industrial usability

The seam welding heads according to the invention can be used in all electric resistance seam welding machines, where, in particular, the substantially lower power required for mechanical drive, can replace the previously known embodiments of the seam welding heads. When using the seam welding heads according to the invention, due to their ease of operation, only one of the pair of heads can be used as a driven head even in cases where both heads had to be used as driven and hitherto unnecessary use of the two heads reduce the cost of the machine. The use of the seam welding heads according to the invention will also simplify operation, increase productivity and reduce costs by eliminating the very frequent relubrication and replacement of worn sliding contact parts.

Claims (5)

PATENT CLAIMS Seam welding head with a fixed part attached to a welding machine and a rotating part carrying a disc electrode, characterized in that on the fixed part (1) there is a first contact path (2), on the rotary part (3) there is a second contact path (4) ) and between the contact paths (2, 4) there are contact bodies (5), wherein in the contact surfaces of the contact bodies (5) with the contact paths (2, 4) the pressure bias is created by a spring (9); (2) also the second contact path (4) has the form of coaxial rotating, preferably conical, surfaces and the contact bodies (5) are preferably in the form of cones, spherical rollers or rollers, further in that the fixed part (1), rotary part (3) The contact bodies (5) are also made of copper-containing alloys and that there are gaps between the contact paths (2, 4) and the contact bodies (5) for the coolant flow. Seam welding head according to claim 1, characterized in that the contact bodies (5) are hollow and mounted on the pins (7) of the crown (6). Seam welding head according to claim 1, characterized in that the spring (9) is a compression, preferably helical cylindrical, and is inserted between the fixed part (1) and the rear bearing (12). A seam welding head according to claim 1, characterized in that the spring (9) is twisted and is interposed between the fixed part insert (1) and the tensioning device (19). Seam welding head according to claim 1, characterized in that the spring (9) has the shape of two parallel arms formed by cutting the bracket (18) in its left part.