Welding bell and welding device

Abstract

Welding bell (120), comprising, a first end (121) which can be brought into contact with an object to be welded and a second end (122) which is opposite the first end (121), wherein the welding bell (120) can be fastened via the second end (122) to a second end (112) of a stud loading device (110) with a connecting element (114), wherein the welding bell (120) delimits a stud receiving space (141), wherein the welding bell (120) comprises at its first end (121) a bellows (140) and a fastening means (150) adjacent to the bellows (140) for fastening the bellows (140) to a housing body (160), and wherein the welding bell (120) comprises the housing body (160) which is fastened to the fastening means (150), wherein the fastening means (150) is arranged between the bellows (140) and the Housing body (160) is arranged, characterized in that the fastening means (150) has a free inner diameter (153) and the housing body (160) has a fourth outer diameter (162) at an end facing the first end (121) of the welding bell (120), wherein the housing body (160) with the fourth outer diameter (162) is inserted into the free inner diameter (153) of the fastening means (150).

Description

The invention relates to a welding bell and a welding device for welding a bolt to a workpiece.The increasing automation of manufacturing processes in the automotive industry also requires a constant search for technical innovation and its technical implementation for the welding of bolts during body manufacturing.It is known during a welding process to delimit the welding region from the environment by means of a welding bell, as a result of which a welding chamber is formed. When inert gas is introduced into the welding chamber, swirling occurs, which leads to intensive mixing with the ambient air already previously located in the welding chamber. The ambient oxygen which is located in the welding chamber generally leads to oxidation or to smoke marks on the welding result during the welding process. This results in a disadvantageous welding result of the welded bolt, so that machining may have to be carried out.DE 10 2016 217 499 A1 discloses a welding device for welding a welding element to a workpiece. The welding device comprises a welding element holder for holding the welding element, wherein a longitudinal axis is defined by the welding element holder, and a coil extending around the welding element holder for generating a magnetic flux for moving an arc, wherein the coil is formed extending over a longitudinal section with respect to the longitudinal axis. The welding device comprises a protective gas inlet space for the entry of a protective gas into the welding device, wherein the protective gas inlet space is formed on a second side of the longitudinal section opposite the first side with respect to the longitudinal axis. Furthermore, a protective gas channel arrangement is provided which conductively connects the protective gas inlet space to the welding chamber for the protective gas, wherein the protective gas inlet space and / or the protective gas channel arrangement has a filter arrangement for influencing a flow of the protective gas.DE 20 2007 007 226 U1 discloses a device for having a component, in particular arc welding. The device comprises a bolt holder with which the held bolt is moved along an axis in a first direction towards the workpiece in order to connect the bolt to the workpiece. Furthermore, the device has a protective gas feed for carrying out the welding process under a protective gas atmosphere, wherein the protective gas is discharged during the welding process substantially in a second direction which is oriented opposite to the first direction. The device also comprises an elastic sealing sleeve which is designed in the manner of bellows and is arranged relative to the bolt holder in such a way that a welding space which is bounded by the workpiece, the bolt holder, the bolt and the sealing sleeve and through which the protective gas flows is sealed off from an external environment during the welding operation, so that the protective gas can escape only in the second direction.US 5 811 055 A discloses a welding system comprising a gas purging system mounted on the torch. The polluting gas is removed from the workplace, thereby preventing defects caused by polluting gases and isolating the heat affected area. This procedure extends the cooling process of the weld pool. The system also includes an auxiliary gas source that is controlled independently of the primary inert gas stream so that auxiliary gas streams can be introduced into the cabin without disturbing the primary gas stream.DE 197 13 732 A1 discloses a submergible device for thermal processing. The apparatus includes a burner having a heat source, a burner housing and an inlet for pressurized gas, a shielding gas nozzle mounted to the burner housing and surrounding at least a portion of the heat source, the shielding gas nozzle having a distal end. The apparatus further comprises a baffle made of a resilient, heat resistant spring material disposed in a closed loop and supported by the distal end of the shielding gas nozzle.GB 2 534 922 A discloses a welding device having a welding head, a control unit and a gas line. The conduit extends between the control unit and the welding head and supplies a gas to the welding head. A flow rate determining device is arranged to determine the flow rate of the gas flowing through the gas conduit between the control unit and the welding head. An optical or acoustic warning signal can be generated via a display if the ascertained gas flow rate is above or below a predetermined minimum / maximum value.JP H03-258 462 A discloses an apparatus for performing high quality stud welding and uniform weld reinforcement on the entire periphery by advancing and moving a stud rod at high speed until the surface of the molten pool is reached in a state of arc generated from the front end of the stud rod, and then advancing and moving the stud rod at low speed.It is an object of the invention to provide an adaptable device which improves the state of the art.For this purpose, according to the invention, a welding bell according to claim 1 and a welding device according to claim 9 with the welding bell according to claim 1 are provided.Advantageous embodiments can be taken from the dependent claims and the description.An object of the invention is a welding bell, wherein the welding bell comprises a first end, which can be brought into contact with an object to be welded, and a second end, which is opposite the first end. The welding bell can be fastened via the second end to a second end of a bolt loading device, in particular by means of a connecting element. The welding bell delimits a bolt receiving space, wherein the welding bell comprises a bellows at its first end and a fastening means adjoining the bellows for fastening the bellows to a housing body. The welding bell also comprises the housing body which is fastened to the fastening means, wherein the fastening means is arranged between the bellows and the housing body. The housing body includes a first end of the housing body and a second end of the housing body. The first end of the housing body points in the direction of the first end of the welding bell and the second end of the housing body points in the direction of the second end of the welding bell. The fastener includes a first end of the fastener and a second end of the fastener. The first end of the fastening means points in the direction of the first end of the welding bell and the second end of the fastening means points in the direction of the second end of the welding bell.In an advantageous embodiment, the bellows extends in the longitudinal direction or along the longitudinal axis of the welding bell, i.e. from the first end of the welding bell in the direction of the second end of the welding bell. The bellows can be compressed in the longitudinal direction or along the longitudinal axis of the welding bell and, after the welding bell has been placed on the object to be welded, closes off the bolt receiving space of the welding bell from the ambient air. Closing means that entry of the ambient air into the welding bell is reduced, preferably avoided.The bellows is a flexible component which can be used to compensate movements of the welding bell and / or to seal the welding bell from the ambient air. The bellows consists of several interconnected folds which make it possible to expand and fold together. The bellows serves to keep away dust, dirt or other contaminants, simultaneously to allow movements and to close off the bolt receiving space of the welding bell from the ambient air. The bellows can be designed in the form of a truncated cone or cylinder. The truncated cone or cylinder comprises a plurality of circularly encircling folds which make it possible to compress the bellows or the truncated cone. The bellows can be connected to the fastening means via a lip of the fastening means over which it is pulled. The lip may be disposed at the first end of the fastener. A lip is to be understood as a projection-like elevation on a surface. Alternatively or additionally, the bellows can be connected to the fastening means via a clamp and / or a clamping screw connection, in particular by grub screws. For this purpose, the fastening means can comprise a circumferential annular groove. The attachment means may comprise the lip over which the bellows is drawn for attachment via the lip towards the first end of the welding bell. The fastening means has a first outer diameter in the region of the lip. The fastening means can have a second outer diameter in the direction of the second end of the welding bell, wherein the fastening means narrows and forms the circumferential annular groove, whereby the lip is formed. Further towards the second end of the welding bell, the fastening means has a thickening with a third outer diameter, wherein the third outer diameter is equal to or greater than the first outer diameter and greater than the second outer diameter. The second outer diameter of the circumferential annular groove is smaller than the first and third outer diameters. The fastening means comprises a free inner diameter which can be produced, for example, by hollow drilling. The free inner diameter serves to receive the bolt loading device or the gas line. The fastening means comprises three bores with an internal thread in the region of the third outer diameter. The three bores extend in the region of the third outer diameter from the outside of the fastening means in the direction of the free inner diameter of the fastening means as far as the free inner diameter. The bores can preferably be arranged radially offset relative to one another by 120 degrees. The fastening means can be circular in individual regions or as a whole or in regions.The bellows can be formed from plastic. Silicone or polyurethane can preferably be used for this purpose, since these materials have advantageous mechanical and chemical properties.Polyurethane (PU) is wear-resistant and has high tear strength and very good compressive strength. PU can be made elastic or hard via chemical additions and can accordingly be selected from very flexible to a little flexible.The bellows made of silicone can be designed to be very flexible. Such a bellows is very resistant to chemicals, high temperatures and aging. In addition, the bellows made of silicone dampens the transmission of vibrations.In an advantageous embodiment, the welding bell comprises the housing body in the region of the second end, wherein the housing body has at least three gas feed openings for feeding protective gas into the bolt receiving space of the welding bell. The housing body can be formed in the region of the at least one gas supply opening or as a whole from plastic, in particular from polytetrafluoroethylene (PTFE) or PVC. The production from plastic makes it possible to easily adapt to different bolt types with different diameters of the bolt loading device. The housing body can be configured in an annular manner entirely or in the region of the at least one gas supply opening. The at least one, preferably three, gas feed openings can be arranged radially on the housing body and pass through the latter radially from an outer region into the bolt receiving space. This means that the gas feed openings extend from radially outside on the housing body through the housing body into the bolt receiving space or a free inner diameter of the housing body. The free inner diameter of the housing body can be produced, for example, by hollow drilling. The outer region is the air space surrounding the welding bell with ambient air. In an advantageous embodiment, the at least three gas feed openings can be arranged radially around the housing body.The at least three gas supply openings can be arranged uniformly around or on the circumference of the housing body or the welding bell. A uniform arrangement of the gas feed openings is advantageous in order to achieve the most homogeneous or identical mixing ratio of gas possible everywhere in the bolt receiving space or in the welding bell. In an advantageous embodiment, the gas feed openings can be arranged uniformly distributed on a circumference of the housing body, in particular offset radially with respect to one another by 120 degrees. The gas supply openings can be used for supplying a protective gas. By using three gas supply openings, the gas flows more slowly into the bolt receiving space or the free inner diameter of the housing body. This reduces turbulence, which has a negative effect on the welding result. The inert gas may be argon, for example. Protective gas can be required in order to displace ambient air located in the welding bell and thereby prevent oxidation of a welding point by the oxygen contained in the ambient air.In a further advantageous embodiment, the free inner diameter of the housing body from the direction of the second end of the welding bell can be designed to receive an adapter for forming a connecting element. The connecting element can be designed as a screw connection. Alternatively or additionally, the connecting element can also be designed as a latching plug connection. The adapter for the connecting element can be inserted into the free inner diameter of the housing body for fastening in the direction of the second end of the housing body. The adapter can be configured such that it closes off the housing body or the welding bell by being inserted into the free inner diameter of the housing body in the direction of the second end of the housing body. The adapter can likewise comprise a free inner diameter for passing a bolt that can be fed into the bolt receiving space via a transport channel of the bolt loading device. For fastening the adapter in the housing body, the housing body can comprise bores with an internal thread, which extend from the outside of the housing body radially in the direction of the free inner diameter of the housing body. The bores can preferably be arranged radially offset relative to one another by 120 degrees. The bores with the internal thread can be arranged such that screws inserted into the internal thread clamp the adapter in the free inner diameter of the housing body when the adapter is inserted. The adapter may comprise a union nut. The union nut can be screwed onto a thread arranged at the second end of the bolt loading device in order to connect the bolt loading device to the housing body or the welding bell. Alternatively, the adapter can comprise a thread instead of the union nut and the bolt loading device can comprise a union nut at its second end for fastening the welding bell. In the case of the screw connection, the connecting element is to be understood as comprising the thread and the union nut. Alternatively, a hollow tube with the free inner diameter and a coupling element can be provided for forming the latching plug connection. The housing body includes a taper to a fourth outer diameter at the first end of the housing body toward the first end of the weld cup. The part of the housing body with the fourth outer diameter can be inserted into the free inner diameter of the fastening means at the second end of the fastening means and connected to the fastening means by a clamping connection with screws in the three bores of the fastening means. For this purpose, the fourth outer diameter of the housing body is smaller than the free inner diameter of the fastening means. The clamping connection can alternatively be formed by a clamp or by the screws. Preferably, the three screws for fastening the housing body to the fastening means can be arranged radially in the fastening means offset by 120 degrees with respect to one another.In a further embodiment, the fastening means for fastening the bellows to the housing body can be arranged between the housing body and the bellows. The fastening means can be configured in a circular manner and be detachably connected to the housing body at a first end.According to the invention, the housing body comprises, at the end facing the first end of the welding bell, a fourth outer diameter which is inserted into the free inner diameter of the fastening means.At the first end of the fastening means, which points in the direction of the first end of the welding bell, the fastening means can be configured to fasten the bellows to the fastening means. The mounting of the bellows on the mounting means can be effected via a lip, over which the bellows is pulled. This fastening can be considered advantageous since no further fastening means are required for this purpose.The fastening means can be designed as a metal ring and in particular consist of or comprise aluminum, copper, steel or brass. The metallic configuration serves for the purpose of uniformizing the field, which has a positive effect on a welding result. Due to the modular construction of the welding bell in bellows, fastening means and housing body, the device can be adapted to different bolt diameters by adapting the individual components.In a further advantageous embodiment, the welding bell comprises a bolt holder arranged in the bolt receiving space for holding a bolt that can be supplied via the transport channel. The bolt holder can be spring-loaded or designed purely via the restoring force inherent in the material to hold the bolt. The restoring force, which can also be referred to as the restoring effect, is the force with which a material is formed back into its original shape. This holds or clamps the bolt after it has been supplied. A bolt holder holds the bolt at the end opposite from the tip of the bolt at which an arc is generated during welding. Holding takes place only before and during welding.The bolts to be welded may be made of alloyed, unalloyed, stainless and heat resistant steels.In an advantageous embodiment, the at least three gas feed openings can each be designed as a quick coupling for connecting a hose. For this purpose, the quick coupling can be designed as a plug connection for a hose for supplying gas.In a further advantageous embodiment, the welding bell comprises, in the region of its second end, an annular magnet which surrounds the feedable bolt. The magnet can surround the bolt receiving space in an annular manner, wherein the longitudinal axis runs through a free inner diameter of the annular magnet. The magnet serves to shape the magnetic field generated by a second current required for welding. The magnet can be designed as a neodymium magnet. The ring-shaped magnet may be disposed inside or outside the case body.A further subject matter according to the invention is a welding device with a welding bell according to at least one of the embodiments described above, wherein the welding device comprises a bolt loading device, the welding bell, a base unit and a connecting element, wherein the bolt loading device is hollow and delimits a transport channel, wherein a bolt to be welded can be supplied to a first end of the bolt loading device and can be moved via a (motive) gas from the first end of the bolt loading device via the transport channel in the direction of the second end of the bolt loading device and thus into the bolt receiving space of the welding bell, wherein the welding bell is fastened with the connecting element by its second end to the second end of the bolt loading device.In an advantageous embodiment, the base unit comprises a loading device with a loading pin for pressing the feedable bolt into the bolt holder. After the feeding of the bolt through the transport channel, the bolt can be pressed into the bolt holder via the loading pin, which is located in the base unit and can be movable in the direction of the bolt. The bolt holder is bent by the bolt on the bolt due to the force of the loading pin and subsequently holds or clamps the bolt. The loading pin executes a movement along the longitudinal axis. The loading pin can be moved by the bolt loading device in the direction of the longitudinal axis and can be guided through the bolt loading device.In a further advantageous embodiment, the base unit comprises an adjusting device for moving the welding bell in the longitudinal direction or along the longitudinal axis of the welding bell. The adjusting device is arranged at a third end of the bolt loading device and / or fastened thereto. The third end of the bolt loading device can be guided into the base unit. The displacement of the adjusting device can take place in the longitudinal direction. The adjusting device can be designed as an electric actuator or as a pneumatic cylinder. The electric actuator, which can be designed in particular as a servomotor, has the advantage that the welding bell can be moved precisely in the range of tenths of a millimeter and with low noise. The welding bell can be moved in the longitudinal direction of the welding bell.In an advantageous embodiment, the bolt charging device is designed for transmitting a first current and for transmitting a second current. The bolt loading device is connected with a third end in an electrically conductive manner to a power source arranged in the base unit. The bolt holder is electrically conductively connected to the bolt loading device, wherein the first current and the second current flow via the second end of the bolt loading device via the bolt holder into the one feedable bolt during a welding process and from there flow into an object to be welded.In an advantageous embodiment, the welding bell can be used in a method for welding a bolt according to the welding device described above. The method may comprise the following method steps:supplying the stud into the welding bell;placing the bolt on an object to be welded to the bolt;supplying shielding gas into a bolt receiving space of the welding bell;energizing the stud with a first current;lifting the stud and / or the welding bell from the object to be welded at a defined distance, wherein a pre-arc is ignited;energizing the stud with a second current to ignite a main arc;dipping the stud into a fused surface of the object to be welded.The individual method steps can be carried out in any desired order. The pre-arc can be weaker with respect to the current intensity than the main arc.Preferably, a short stroke ignition method may be used for welding the bolt. The short-stroke ignition method has the advantage that the bolt can be welded to a metal sheet by a short, flat burn-in. The welding time may be up to 200 milliseconds and the second current may be up to 1400 A. The first current and the second current can each be a direct current.During the lifting of the stud, an end face of the stud and an approximately equally large surface on the object to be welded are melted by the pre-arc. The object to be welded or the fused surface is cleaned by the pre-arc. The distance by which the bolt is lifted can be up to 2 mm. This lifting can be effected by an adjusting device. In a further advantageous embodiment, the welding bell with the bolt is prestressed to a defined distance by a magnet coil against a spring. A gap is thus formed between the bolt and the object to be welded. The spacing can be provided by a spacer on the welding bell or the base unit.By triggering the welding process by an operator or a controller after a set welding time has elapsed, the magnet coil is released or the adjusting device is actuated and the bolt moves by the spring or the adjusting device in an accelerated manner toward the welding object and dips into the fused surface up to a preset depth.The invention is described below purely by way of example with reference to the drawings. The following are shown: FIG. 1 shows a welding device with a welding bell according to an embodiment of the invention in a plan view; and FIG. 2 shows a welding device with a welding bell according to an embodiment of the invention in front view; and FIG. 3 shows a welding bell according to an embodiment of the invention.FIG. 1 shows a welding device 100. The welding apparatus 100 includes a bolt loading device 110, a welding bell 120 and a base unit 170. The welding bell 120 comprises a first end 121 which can be brought into contact with an object to be welded and a second end 122 which is opposite the first end 121. The welding bell 120 is fastened via the second end 122 to a second end 112 of the bolt loading device 110, in particular by means of a connecting element 114 which is designed as a screw connection. The connecting element 114 or the screw connection is designed as a union nut which is screwed onto a thread. The welding bell 120 delimits a bolt receiving space ( 141 in FIG. 2 ), which is not shown in FIG. 1. The welding bell 120 comprises at its first end 121 a bellows 140, a fastening means 150 adjoining the bellows 140 for fastening the bellows 140 and a housing body 160. The fastener 150 is fixed to the case body 160, and thus the bellows 140 is fixed to the case body 160 via the fastener 150. For this purpose, the bores 152 comprise internal threads, not shown, in which respective grub screws 151 are arranged for fastening the fastening means 150 to the housing body 160. The bellows 140 is fastened to the fastening means 150 via a lip ( 159 in FIG. 3 ), over which it is pulled. The casing body 160 includes three gas supply ports 161 each offset by 120 degrees. The bolt loading device 110 delimits a transport channel 113, wherein a bolt to be welded can be fed to a first end 111 of the bolt loading device 110 and can be moved via a (motive) gas from the first end 111 of the bolt loading device 110 via the transport channel 113 in the direction of the second end 112 of the bolt loading device 110 and thus into the bolt receiving space (141 in FIG. 2 ) of the welding bell 120. The bolt ( 180 in FIG. 2 ) is held in the bolt receiving space ( 141 in FIG. 2 ) by a bolt holder. The bellows 140 is compressible in the direction of the longitudinal axis 190 of the welding bell 120, that is to say from the first end 121 of the welding bell 120 in the direction of the second end 122 of the welding bell 120. The bolt charging device 110 is designed for transmitting a first current and for transmitting a second current. The bolt loading device 110 is electrically conductively connected by a third end 115 to a power source arranged in the base unit 170. In this case, the bolt holder is electrically conductively connected to the bolt loading device 110, wherein the first current and the second current flow via the second end 112 of the bolt loading device 110 via the bolt holder into the one feedable bolt 180 during a welding process and from there flow into the object to be welded.FIG. 2 shows a welding device 100 in a front view from the direction of the first end 121 of the welding bell 120 so that the bolt receiving space 141 can be seen. The bolt 180 is surrounded annularly by the fastening means 150. Behind the fastening means is the housing body 160 with the gas supply openings 161. The gas supply openings 161 extend from radially outside of the housing body 160 through the housing body 160 into the bolt accommodation space 141 and the free inner diameter of the housing body 160, respectively. The bolt 180 is arranged in the bolt receiving space 141. When viewed from the first end 121 of the welding bell 120 into the open side of the bellows 140, the housing body 160 is visible, which closes off the bolt receiving space 141 at the second end of the welding bell (122 in FIG. 1 ). Below the welding bell 120 the base unit 170 is visible.FIG. 3 shows a welding bell 120. The welding cup 120 includes the housing body 160 having a first end of the housing body 165 and a second end of the housing body 166. The first end of the housing body 165 points toward the first end of the welding bell 121 and the second end of the housing body 166 points toward the second end of the welding bell 122. The housing body 160 comprises a free inner diameter 164 and three gas supply openings 161, two of which are visible. In addition, three bores 163 are arranged on the outer surface of the housing body, one of which is visible. The bores 163 extend symmetrically offset to one another, i.e. spaced apart by 120 degrees in the direction of the free inner diameter 164 of the housing body 160. The internal threads in the bores 163 are not shown. The housing body 160 includes a fourth outer diameter 162 at its first end 165.The welding bell 120 further comprises the shown fastener 150, wherein the fastener 150 comprises a first end of the fastener 157 and a second end of the fastener 158. The first end of the fastening means 157 points in the direction of the first end of the welding bell 121 and the second end of the fastening means 158 points in the direction of the second end of the welding bell 122. The fastener 150 includes a free inner diameter 153 at the second end of the fastener 158. The housing body 160 having the fourth outer diameter 162 or the first end of the housing body 165 can be inserted into the free inner diameter 153 of the fastening means 150. On the outer surface at the second end of the fastener 158 there are three bores 152, one of which is visible. The bores 152 comprise internal threads, not shown, in which grub screws 151 for fastening the fastening means 150 to the housing body 160 are arranged in each case. The fastening means 150 comprises at its first end 157 a first outer diameter 154 and a second outer diameter 155 adjoining thereto in the direction of the second end 158, wherein the second outer diameter 155 is smaller than the first outer diameter 154, whereby a lip 159 is formed. A third outer diameter 156 adjoins the second outer diameter 155, wherein the third outer diameter 156 is formed to be equal to or greater than the first outer diameter 154 and greater than the second outer diameter 155. This forms a circumferential annular groove. The figure also shows the pleated bellows 140, wherein the pleated bellows delimits a bolt receiving space ( 141 in FIG. 2 ).List of reference characters100 Welding device 110 Bolt loading device 111 First end of the bolt loading device 112 Second end of the bolt loading device 113 Transport channel 114 Connecting element 115 Third end of the bolt loading device 120 Welding bell 121 First end of the welding bell 122 Second end of the welding bell 140 Bellows 141 Bolt receiving space 150 Fastening means 151 Grub screw 152 Bore 153 Free inner diameter 154 First outer diameter 155 Second outer diameter 156 Third outer diameter 157 First end of the fastening means 158 Second end of the fastening means 159 Lip 160 Housing body 161 Gas supply opening 162 Fourth outer diameter 163 Bore 164 Free inner diameter 165 First end of the housing body 166 Second end of the housing body 170 Base unit 180 Bolt 190 Longitudinal axis

Claims

Welding bell (120) comprising a first end (121) which can be brought into contact with an object to be welded and a second end (122) which is opposite the first end (121), wherein the welding bell (120) can be fastened via the second end (122) to a second end (112) of a bolt loading device (110) having a connecting element (114), wherein the welding bell (120) delimits a bolt receiving space (141), wherein the welding bell (120) comprises at its first end (121) a bellows (140) and a fastening means (150) adjoining the bellows (140) for fastening the bellows (140) to a housing body (160), and wherein the welding bell (120) comprises the housing body (160) which is fastened to the fastening means (150), wherein the fastening means (150) is arranged between the bellows (140) and the housing body (160), characterized in that the fastening means (150) has a free inner diameter (153) and the housing body (160) has a fourth outer diameter (162) at an end facing the first end (121) of the welding bell (120), wherein the housing body (160) with the fourth outer diameter (162) is inserted into the free inner diameter (153) of the fastening means (150).Welding bell (120) according to claim 1, characterised in that the bellows (140), which extends along a longitudinal axis (190) of the welding bell (120), i.e. from the first end (121) of the welding bell in the direction of the second end (122) of the welding bell (120), is compressible and, after placing the welding bell (120) on the object to be welded, closes off the bolt receiving space (141) of the welding bell (120) with respect to the ambient air.Welding bell (120) according to one of the preceding claims, characterized in that the housing body (160) has at least three gas feed openings (161) for feeding protective gas into the bolt receiving space (141) of the welding bell (120), wherein the gas feed openings (161) extend from radially outside on the housing body (160) through the housing body (160) into the bolt receiving space (141).Welding bell (120) according to claim 3, characterised in that the gas feed openings (161) are uniformly distributed over a circumference of the housing body, in particular are arranged radially offset relative to one another by 120 degrees.Welding bell (120) according to claim 3 or 4, characterised in that the at least three gas feed openings (161) are each designed as a quick coupling for connecting a hose.Welding bell (120) according to one of the preceding claims, characterized in that the welding bell (120) comprises a bolt holder arranged in the bolt receiving space (141) for holding a bolt (180) which can be fed in via a transport channel (113).Welding bell (120) according to one of the preceding claims, characterized in that the welding bell (120) comprises, in the region of its second end (122), an annular magnet which surrounds the bolt receiving space (141) in an annular manner.Welding bell (120) according to one of the preceding claims, characterized in that the free inner diameter (164) of the housing body (160), as seen from the direction of the second end of the welding bell (122), is designed to receive an adapter for forming the connecting element (114).Welding device (100) comprising a bolt loading device (110), a base unit (170), the welding bell (120) according to one of claims 1 to 8 and a connecting element (114), wherein the bolt loading device (110) delimits a transport channel (113), wherein a bolt (180) to be welded can be fed to a first end (111) of the bolt loading device (110) and can be moved via a gas from the first end (111) of the bolt loading device (110) via the transport channel (113) in the direction of a second end (112) of the bolt loading device (110) and thus into the bolt receiving space (141) of the welding bell (120), wherein the welding bell (120) is fastened with the connecting element (114) at the second end (122) thereof to the second end (112) of the bolt loading device (110).

Images