DE-102015221384-B4 - Lift ignition welding device

DE102015221384B4DE 102015221384 B4DE102015221384 B4DE 102015221384B4DE-102015221384-B4

Abstract

Welding device for welding a bolt (1) to a workpiece (2) by means of an electric arc according to the lift ignition welding process, comprising - a case (3), - Means of generating a welding current, - a bolt holder (5) attached to the housing (3) for holding the bolt (1), - an electrical conductor arrangement (6) for conducting the welding current, wherein the conductor arrangement (6) has a contact surface area (7) which is designed to be positioned electrically in contact with the workpiece (2), wherein the conductor arrangement (6) is fixedly connected to the housing (3) or is resiliently mounted on the housing (3) or is designed as part of the housing (3), characterized in that the welding device further - a protective gas bell (20) as well as - comprising a magnetic coil (8) or several magnetic coils for generating a transverse magnetic field (9) acting on the arc, wherein the conductor arrangement (6) is designed as part of the protective gas bell (20).

Inventors

Heinz Soyer jun.
Andreas Walter Jilg

Assignees

Bolzenschweißtechnik Heinz Soyer GmbH

Dates

Publication Date: 20260513
Application Date: 20151102

Claims (15)

Welding device for welding a stud (1) to a workpiece (2) by means of an electric arc according to the lift-arc welding process, comprising: - a housing (3), - means for generating a welding current, - a stud holder (5) mounted on the housing (3) for holding the stud (1), - an electrical conductor arrangement (6) for conducting the welding current, wherein the conductor arrangement (6) has a contact surface area (7) which is designed to be positioned electrically in contact with the workpiece (2), wherein the conductor arrangement (6) is fixedly connected to the housing (3) or is resiliently mounted on the housing (3) or is designed as part of the housing (3), characterized in that the welding device further comprises: - a shielding gas bell (20) and - a magnetic coil (8) or several magnetic coils for generating a transverse magnetic field (9) acting on the electric arc, wherein the conductor arrangement (6) is designed as part of the shielding gas bell (20).
Welding device according to Claim 1 , in which the conductor arrangement (6) extends at least partially inside the magnetic coil (8) and/or outside the magnetic coil (8).
Welding device according to Claim 1 or 2 , in which the contact surface area (7) has a ring shape that extends around a longitudinal axis (L) defined by the bolt holder (5).
Welding device according to Claim 3 , in which the design is such that the contact surface area (7) - viewed in a cross-section normal to the longitudinal axis (L) - extends over the projection of the magnetic coil (8) or the magnetic coils.
Welding device according to Claim 1 or 2 , wherein the contact surface area (7) has at least two contact surface area portions (10) which extend within an annular area which runs around a longitudinal axis (L) defined by the bolt holder (5).
Welding device according to one of the preceding claims, wherein the design is such that the ladder arrangement (6) is resiliently mounted parallel to a longitudinal axis (L) defined by the bolt holder (5) relative to the housing (3).
Welding device according to Claim 5 , in which the design is such that the conductor arrangement (6) is resiliently mounted parallel to a longitudinal axis (L) defined by the bolt holder (5) relative to the housing (3), wherein the contact surface area portions (10) are each arranged to be resiliently movable independently of each other relative to the housing (3).
Welding device according to Claim 6 or 7 , further comprising - a control device for controlling the welding current, wherein the design is such that the welding current is released by the control device depending on a pressure acting between the conductor arrangement (6) and the housing (3).
Welding device according to Claim 7 , further comprising - a control device for controlling the welding current, wherein the design is such that the welding current is released by the control device depending on a pressure acting between the conductor arrangement (6) and the housing (3), and - several pressure sensing elements connected to the control device for sensing pressures between each of the contact surface area parts (10) and the housing (3).
Welding device according to Claim 9 , in which the design is such that the welding current can only be switched on by the control device if each of the pressures exceeds a certain minimum value.
Welding device according to Claim 10 , in which the design is such that the welding current is switched off by the control device as soon as one of the pressures falls below the specified minimum value.
Welding device according to one of the Claims 8 until 11 , further comprising - a measuring arrangement connected to the control device for measuring an electrical resistance existing between the workpiece (2) and the conductor arrangement (6).
Welding device according to Claim 12 , in which the design is such that the welding current is switched off by the control device as soon as the electrical resistance exceeds a certain minimum value.
Welding device according to one of the preceding claims, further comprising - a ground wire mechanically connected to the housing (3) and a supply wire mechanically connected to the housing (3) for conducting the welding current, wherein the ground wire and the supply wire are mechanically connected to each other.
Welding device according to one of the preceding claims, further comprising - a release button or several release buttons for a two-hand control.

Description

The invention relates to a welding device for welding a bolt to a workpiece using an electric arc according to the lift-arc welding process. In stud welding with lift ignition, according to the state of the art, as in 7a As sketched, the welding circuit is closed by a ground cable 100 using a ground clamp 105 on the workpiece 101 and bolts 102. Therefore, at least one ground cable 100 is attached to the workpiece 101 and connected with a - in 7a The stud welding gun 103, or a stud welding head, only vaguely outlined, completes the necessary welding circuit for the stud welding process. It is further known that – as in 7b As outlined, better welding results can be achieved by symmetrically applying two corresponding ground connections. However, in practical welding applications, especially with complex component geometries, it is often not possible to establish a symmetrical ground connection as shown. 7b outlined, to be implemented. With a one-sided or asymmetrical ground connection, the arc is carried out by the magnetic field of the welding current, as in 7a Indicated by an arrow, the weld is deflected to one side (blowing effect). This poses a practical problem, as the weld quality of elements welded under blowing effect is significantly reduced. document GB 795 481 A shows a stud welding process under protective gas. Document DE 27 13 288 A1 shows a stud welding machine. Document DE 26 47 845 A1 Figure 10 shows a stud welding gun with multiple contact surface areas for electrically contacting a workpiece. Document 10 2004 051 389 B4 shows a stud welding process with a transverse magnetic field acting on the arc. DE 102 21 387 C1 Shows stud welding with an asymmetrically generated magnetic field. Document US 4 182 949 A Shows an underwater stud welding machine. Document DE 20 14 189 A shows a stud welding process with a protective collar for electrical contacting a workpiece. From the EP 1 649 962 A1 A stud welding process using a radially symmetrical magnetic field (SRM) is known. The use of the radially symmetrical magnetic field significantly reduces the undesirable effect of blow-through. This allows for simplified ground clamping on the component. However, even with an asymmetrical ground connection in the SRM process, blow-through can negatively affect the quality of the weld. The invention is based on the objective of providing a corresponding improved welding device; in particular, the welding device should enable the achievement of high-quality welded joints with particularly simple handling. This problem is solved according to the invention with the subject matter specified in the independent claim. Specific embodiments of the invention are specified in the dependent claims. According to the invention, a welding device is provided for welding a stud to a workpiece using an electric arc according to the lift-arc welding process. The welding device comprises a housing, means for generating a welding current, a stud holder mounted on the housing for holding the stud, and an electrical conductor arrangement for conducting the welding current. The conductor arrangement has a contact surface area designed to be electrically contacted on the workpiece. Furthermore, the welding device comprises a magnetic coil or several magnetic coils for generating a transverse magnetic field acting on the electric arc, as well as a shielding gas bell, wherein the conductor arrangement is designed as part of the shielding gas bell. The conductor arrangement is either rigidly connected to the housing, resiliently mounted on the housing, or designed as part of the housing. This offers the advantage that clamping a ground connection to the workpiece is not required to set the bolt. This significantly simplifies the handling of the welding device. Furthermore, the conductor arrangement allows for a particularly symmetrical ground connection. This reduces or practically eliminates blow-by, resulting in a particularly high-quality weld. As previously described, the welding device has one or more magnetic coils to generate a transverse magnetic field that acts on the arc. This allows a magnetically moving arc to be generated in accordance with the SRM process, enabling the use of a reduced welding current to produce the weld. This reduces the maximum current density of the welding current and thus the risk of damage, particularly to the workpiece or conductor assembly. Preferably, the conductor arrangement extends at least partially inside and/or outside the magnetic coil. This makes the conductor arrangement particularly suitable as part of a protective gas bell. Preferably, the contact surface area has a ring shape extending around a longitudinal axis defined by the bolt holder. This allows for a particularly symmetrical welding current flow. In the SRM process, this ensures that the current takes the shortest path during the arc's rotation phase at every deflection angle. Furthermore, the design is preferably such that t