DE1540866A1 - Welding device - Google Patents

Description

Welding equipment. The invention relates to the electrical Welding and in particular on stud welding devices used for the one end of an axially extending bolt with the surface of a laterally to connect extending workpiece for any purposes. For example the free end of the stud after it has been welded to the workpiece, be threaded to attach any components to the., component to be able to.

For beam welding devices of the type mentioned above are already various electrical devices have been proposed. At an execution farm Such a device, the bolt is pressed against the workpiece, and the abutting parts of the bolt and the workpiece becomes Energ - z = .- u: one Appropriate energy source supplied. In this case the bolt can with one Be provided projection that with the workpiece in such Way is brought into pressure contact that the discharge of the energy source-over the bolt projection and the workpiece to a destruction of the projection, to one Heating of the abutting parts of the stud and the workpiece to the welding temperature and results in diffusion bonding of the parts under the applied pressure. at Another embodiment may be the pre-tensioned bolt be released to move against the workpiece, so that when it hits the workpiece comes into contact, the heat source is discharged and the vision is produced. at In a further embodiment, the bolt can then be pressed against the workpiece be pulled away from this to draw an arc of light, and afterwards pressed against the workpiece again in order to remove the adjoining parts to join together, in each case the welding currents very high, so there: 3 the devices to be provided for switching these high welding currents work in very harsh conditions. As a result, these switching devices must of severe: execution and require frequent and considerable maintenance.

The E..finaung creates for use with a bolt, welding device of any of the foregoing types a roughly novel switching device, which is characterized by the lack of moving parts and an unusually low weight and which requires a minimum of maintenance while keeping up a v ", irksanies work.

A primary purpose of the invention is to provide an unusually effective Switching circuit for the welding currents in stud welding devices of the aforementioned To create a way in which the switching by means of a gate rectifier, preferably a controlled silicon alignment device. Another purpose of the invention consists in an ä;: haltstromifreis of the specified kind to sct: ape, in which the gate rectifier the. -discharge of a capacitor over uie to each other @ rerschiveiT- @ erideri '.teile controls.

Another purpose of the invention is to create a SclialL, str, oitiicreis of the aforementioned type, in which the control judge the production an arc between the: parts that are welded to one another -: u controls.

@@ i tere @, ecite of the invention go from the following description The invention is illustrated below using two examples in the drawing explained in more detail.

Fig. 1 is a schematic representation of an embodiment of a Stud welding device according to the invention.

I = ig. Fig. 2 is a sectional view on an enlarged scale a: gate rectifier ,. in the facility according to @ Ij-ig. 1 used will can.

Fig. 3 is a schematic representation of a further embodiment a stud welding device according to the invention.

The apparatus shown in Fig. 1 generally comprises a stud welding gun 20, a control circuit 22 and a switching circuit 24. The welding gun 20 is described below in connection with a bolt 26 and a workpiece 28, while thereafter the control circuit 22 and the switching circuit 24 in connection with the operation of the welding gun 20 and the interrelation of the structural parts these circuits, especially in relation to. on the one shown in Fig. 2 controlled Silicon rectifiers are described.

The welding gun 20 contains a chuck 30 for holding the bolts 26. The chuck 30 is reciprocable within the housing 32 of the gun stored, whereby it can be advanced to its extreme position by a spring 3 # and is retractable into its innermost position by an electromagnetic coil 36. That Chuck 30 is arranged to enter housing 32 when the Gun 20 is pressed against the workpiece 28 by hand. Under these circumstances the bolt 26 rests on the ZJerkstück 28. Werin trained as a counter in the company Trigger 38 of the pistol 20 is actuated, the electromagnetic coil 36 is energized and sees the stud 26 away from the workpiece 28, thereby between the stud and the workpiece a pilot arc is generated. Thereafter, the control circuit 22 causes that through A welding current flows through the switching circuit 24 to produce a welding arc to create. At a suitable point in time at which the facing each other Parts of the bolt 26 and the workpiece 28 have been heated in the melted state are, the spring presses 3`t the bolt 26 3.n contact with the workpiece 28, around the Bolt and the workpiece to be firmly connected to each other.

The control circuit 22, which is fed from an alternating current source 37; contains a transformer 39, a rectifier circuit 41 assigned to it and the structural parts mentioned below, the band works in the manner described below. The trigger 38 of the welding gun 20, when actuated, closes a normally open switch 40, energizing a relay 42 and timer relals 4-4, thereby closing normally open contacts 46, 4 and 50 associated with relay 42. As soon as the contacts 50 close, the electromagnetic coil 36 in the welding gun is energized and the chuck 30 is thereby withdrawn into its innermost position in the gun housing 32, so that the ignition arc is generated. When the Izortake 48 of the Relx_-42 in the switching circuit 24 close, the switching circuit 24 generates a welding current between the stud 26 and the workpiece 28 under the control of a controlled silicon rectifier 52 to be described below.

The controlled silicon rectifier 52, which is shown in Fig. 2 in section is shown, forms a controlled line for the welding current, the one DC power source 47 is taken. The silicon controlled rectifier 52 is generally similar to an ordinary rectifier, i. H. he can only go in the forward direction from an anode 54:.: u to a cathode 56 conduct. The controlled silicon rectifier However, 52 blocks in the forward direction until a small voltage, which is called the ignition voltage is designated, between the cathode 56 and a gate electrode 58 is applied. After that, the conductive state remains, even if the gate current is interrupted is until the current flowing between the anode and the cathode is below a given minimum value s.-inkt, which is referred to as the holding current.

As can be seen from FIG. 2, a carrier 60, a pnp structure 62 and a pn structure 64 are located between the anode 54 and the cathode 56 of the rectifier 52. The -pnp structure 62 is composed of silicon layers 66, 68 and 70, and the pn-structure (4 comprising the silicon layer 70 and a Goldarxtimonschicht 72. the gate electrode 58 is verklunden with the structure 64th in essence, the controllable rectifier 52- a pnpr unit having a gate electrode connected to the inner p-Schidt. -ir: In operation, the voltage between the gate electrode and the cathode of the silicon rectifier 52 must be above a predetermined minimum value before conduction can occur. even if the gate voltage is removed until the current falls below a predetermined minimum, at which the Z_; controlled silicon rectifier returns to the forward blocking state, in which the Gate is open.

Switching circuit 24 includes the following components and ar "e2, tet wt-3ise described in Aer 11s olgerd.? der 5f: I: # l tstrc@rifcre.s 2 # + = hi @ # d from the above aselstroincaue: _ l e j; through a transformer 43 and a Glei ".- h2iGhtei @ sc @ ialtung 45 fed, and when closing the i -; Lintaltts 4ü de: -> Relay 42 is between the gate electrode 58 ui ff @ at u @ ä "') of the controlled Silicon rectifier 52 has a potential F- @, @ eugt. Lire 'resistance 74 limited this potential to a safety value in the working range of the controlled silicon gauges. Once this potential is created; becomes the controlled silicon rectifier conductive. Under these conditions, current flows through the welding gun, 20 and from the bolt 26 to the workpiece 28.

At the. End of a welding period determined by the timer relay 44 is, -will open its normally closed F_ontakte 76 and its normally open I << ontakte (6 closed. By closing the Kantakt ; "3 of the time boom relay 411 v: @ is energized by relay 6U, so that its normally open contacts 82 closed and its normally closed Contacts 84 are opened. By opening the contacts 84 of the relay 80 is the charging of a capacitor 86 supplying a reverse voltage is interrupted, and by closing contacts 82 of relay 80, it is sent to the controlled silicon rectifier 52 between its anode 54 and its cathode 56 a reverse voltage in the Manner designed to cause the flow of a reverse current through the @ der Silicon rectifier 52 regained its ability to block forward current or, in other words, turn off the flow of current. The time of this shutdown is very short. and is generally about 10 to 20 microseconds. This shutdown time however, it is short enough to allow the welding current to flow in synchronism with the pressing interrupt the bolt to the workpiece. The controlled silicon rectifier 52 is now in the blocking state and remains in this state until again a full work cycle is initiated. The device shown in FIG generally includes a stud welding gun 90 and a control circuit 92. The control circuit 92 includes a transformer 94 for AC power supply, a Capacitor 96 that if he. is charged, supplies a welding current, a controlled silicon rectifier 98 for charging the capacitor 96 and a second controlled silicon rectifier 100, which the one by the welding gun controls continuous welding current. The Operation of Control Circuit 92 will be discussed in more detail below, and the operation of gun 90 will be explained below in connection with a bolt 102 and a .Werkstück 104 described. , The gun 90 contains a Sl; anrzfutter 106 for holding the bolt 102, the end of which with a Projection 108 is provided. The chuck 106 is within the housing 110 of the Pistol 90 reciprocally mounted, and it is by a spring 112 in his extreme position pressed.

The chuck 106 is arranged so that it is in the housing 110- is moved in when the gun is pressed against the workpiece 104 by hand. As soon as a welding current through the stud 102, its projection 108 and the workpiece $ 10 goes through. the projection 108 is destroyed in a known manner and the bolt 102 under the force of spring 112 in contact with workpiece 104 at a time brought to which the facing parts of the bolt and the workpiece have been heated to the welding temperature by the welding current.

Silicon controlled rectifier 98 illustrates one way of supplying direct current to capacitor 96 in response to alternating current received from transformer 94. This controlled silicon rectifier 98 is identical or similar to that shown in FIG. 2, and it has an anode 114, a cathode 116 and a gate electrode 118 .

The primary 120 of transformer 94 receives AC power via a switch and a fuse. (not shown) supplied. When inserting of the switch occurs at terminals 122 and 124 of the secondary winding of the transformer 94 an alternating voltage. If terminal 124 is negative with respect to terminal 122 current flows (in the direction of electron flow): from the terminal 124 to the Capacitor 96, from this via a resistor 12ö to the cathode 116 of the controlled silicon rectifier 98, via a diode 128, a resistor 130, a selected one Part of a potentiometer 132, between its tap 134 and its end 136, and through a diode 138 to terminal 122. In addition, when terminal 124 in with respect to the terminal, 122 is negative, current through the potentiometer 132 and the Diode 138 and creates a voltage drop between end 140 and the Tap 134 of potentiometer 132.

The handle 134 can be adjusted to turn the potentiometer to generate any voltage between the value zero and a maximum W :: rt, the maximum value being equal to the voltage between ends 140 and 136 of the potentiometer 132 is.

When the voltage on capacitor 96 rises to a value approximately equal to the voltage drop between points 134 and 140 of potentiometer 132, the voltage occurring between gate electrode 118 and cathode 116 of silicon controlled rectifier 98 is less than the minimum Ignition voltage of this rectifier. As soon as the polarity between the terminals 122 and 124 of the Selsundärwier: development of the transformer 94 is reversed in each half cycle of the alternating supply current, the current flowing from the cathode to the anode of the rectifier 38 drops at this point to the value zero. The current is therefore smaller than the holding current, so that: 3 the controlled silicon rectifier a: 8 is switched to the non-conducting state. It remains in this state until, as a result of the deactivation of the partially controlled silicon rectifier 100, a gate current flows again in the manner to be described below.

When the bolt 102 is brought into contact with the workpiece 104 and the trigger 144 of the pistol 90, which is designed as a switch, is operated by hand, a circuit from one side of a rectifier circuit 146 will match Relay 148, trigger switch 144, bolt 102 and over ground to the other side the rectifier circuit 146 is closed. By energizing the relay 148 normally closed contacts 150 of this relay open and normally open contacts 152 of the relay closed. When the contacts 152 are closed between the gate electrode and the cathode of the second silicon controlled rectifier 100 applied a voltage through a resistor 154 on a security value is limited.

A diode 155 prevents a negative voltage from being applied to the gate electrode of the second silicon controlled rectifier 100. A resistor 157, which is connected across the cathode of the silicon rectifier 100 and one side of the capacitor 96, prevents the voltage from rising too quickly (ie the value ) between the anode and the cathode of the controlled silicon rectifier 100. The voltage generated between the gate electrode and the cathode of the rectifier 100 causes this rectifier to be made conductive, so that the welding capacitor 96 is positioned over the bolt 102 and the workpiece 104 discharges, whereby the weld is brought about. A capacitor 156 connected in parallel with relay 148 causes a time delay for analog relay 148 when the trigger switch 144 is opened or when the pistol is moved away from the bolt 102, and it gives the silicon controlled rectifier 100 sufficient time to switch to its blocking state State before the contacts 150 of the relay 148 are closed.

An optionally applicable feature is a charging resistor 126 parallel connected relay 158, which is energized when charging current through the resistor: 126 passes through. By energizing relay 158, associated, normally closed contacts 161 open, whereby. the discharge circuit made ineffective will while a dem Relay 158 parallel connected capacitor 160 serves to ensure that this relay remains energized until the welding capacitor 96 is fully charged.

The invention thus provides a light and effective switch, able to control high welding currents and not moving mechanical ones Has parts that are subject to wear and tear and misalignment.

In the described and illustrated embodiments, in Various modifications can be made within the scope of the invention.

Claims (1)

Claims 1.) gchweißeinrichtung with .Mitteln, the two arrange to be welded together parts in their position relative to each other, and a power source for supplying an electric current of sufficient Ztärke and duration to the welding together of the two parts, characterized by the flow of the electric The rectifier device which controls the current between the parts to be welded to one another and which has an anode, a cathode and a gate electrode and which is made conductive in a single direction when a voltage is applied to its gate electrode which is greater than its ignition voltage and is non-conductive when the current flowing between its Applying a voltage of a desired one Value to the gate electrode. 2.) Welding device according to claim 1, characterized in that the rectifier device has a pnpn structure, with the opposite sides of which the anode and the cathode are connected and with the inner p-view of the gate electrode is connected. j.) Welding device according to claim 1 or 2, characterized in that the energy source has a welding energy supply device and that the anode and the cathode of the rectifier device are effectively connected via this welding energy device and the parts to be welded. Welding device according to Claim 3, characterized in that the welding energy supply device is a capacitive energy storage source. 5.) : welding device according to etem of claims 1 to 4, characterized in that the means for applying a voltage to the gate electrode of the rectifier device have a switch and an impedance which are connected in series; the anode and the gate electrode of the rectifier device are connected. 6.) Welding device with means for inserting two parts to be welded together in FGrm a bolt and your workpiece, an alternating current source and a capacitor on which a charge of sufficient height can be generated to weld the two parts together, characterized by a first rectifier device which has an anode, a cathode and a gate electrode and which is made conductive in a single direction when a voltage is applied to its gate electrode which is greater than its ignition voltage and is non-conductive when that between its anode and its cathode current flowing is less than a holding value and when the voltage is removed from its gate electrode, means which connect the anode and the cathode of this first sliding device between the AC supply source and the capacitor, .tor, means for controlling the to the gate electrode of the first Rectifier device applied chip voltage, a second rectifier device having an anode, a cathode and a gate electrode, and which is rendered conductive in a single direction when a voltage is applied to its gate electrode 'that is greater than their starting voltage, and is nonconductive when the between its anode and its cathode current flowing is less than half the value, means which the anode and the cathode of the second rectifier device work-related via the capacitor and the parts to be welded and a manually operated device for applying the voltage to the gate electrode of the second straightening device. 7.) Welding device according to claim 6, characterized in that each of the two rectifier devices has a pnpn structure, with the opposite sides of which the anode and cathode of the rectifier device in question are connected and with the inner p-Schioht the gate electrode of the rectifier device in question is connected .