JP2624955B2 - Automatically operated capacitor discharge stud welding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention accumulates welding energy in a capacitor from an AC power supply through a rectifier circuit, and applies the accumulated welding energy to a stud mounted on a welding gun and a base metal. The present invention relates to an automatically operated capacitor discharge type stud welding apparatus which can be used in combination with an industrial robot, in which a stud welding is performed by discharging during the stud welding.

[Related Art] Conventionally, various types of capacitor discharge stud welding devices have been proposed and put to practical use. For example, Japanese Patent Publication No. 57-50596 discloses that a switching element is connected between a welded portion composed of a base metal to be welded of a stud and a welding gun and a capacitor connected to a power supply, and this switching is performed. An electronically controlled capacitor discharge stud welding apparatus is disclosed that includes an electronic control circuit that operates the elements in relation to the state of charge of the capacitor. Further, examples of other capacitor discharge type stud welding devices include those disclosed in Japanese Utility Model Publication No. Sho 56-41902 and Japanese Utility Model Publication No. Sho 57-54930. A power supply having a device, a plurality of series-connected capacitors charged by the power supply,
A capacitor discharge type having a switching element inserted in the capacitor charge / discharge circuit and a control circuit for turning on / off the switching element of the capacitor charge / discharge circuit by a trigger signal from a welding gun in response to the charge state of the capacitor. Stud welding machine is shown,
Japanese Patent Publication No. 54930 discloses a capacitor for storing welding energy comprising a plurality of capacitors, a switching device for selectively connecting these capacitors in parallel or in series with each other, and a stud to be welded by the switching device. There is shown a capacitor discharge stud welding apparatus in which capacitors are connected in parallel or in series according to characteristics to obtain optimum welding energy.

In such a conventionally known capacitor discharge stud welding apparatus, it is generally necessary to set the charging voltage level of the capacitor according to the purpose of use, that is, the type (material) and size of the stud to be welded. Therefore, usually, a setting knob on an operation panel provided on the front surface of the welding device main body is turned to obtain an output suitable for a stud to be welded.

By the way, in recent years, due to the development of industrial robots, for example, in an assembly factory, various operations are automated and sequentially performed on a production line, and industrial robots are also used for stud welding, which is one of welding methods. It can be operated automatically. This is effective not only in promoting full automation of the production line, but also in terms of labor saving and worker safety. An example of such an automatically operated stud welding apparatus is described in Japanese Patent Application Laid-Open No. Sho 60-54279.

[Problems to be Solved by the Invention] In such an automatically operated stud welding apparatus, automatic operation is performed from mounting of a stud to be welded to a welding gun mounted on a robot arm to welding of the stud to a base material. However, in actual stud welding, the studs to be welded are not always the same type or the same size, and studs of different sizes or different sizes are often used for the base material. It is required that welding be performed in a prescribed order or in some cases at random. In such a case, in the capacitor discharge type stud welding device of the conventional structure, the output adjustment knob provided on the welding device body is manually operated each time to set the capacitor voltage level to a value suitable for the stud to be welded. There is a need to. Therefore, despite the automatic operation using an industrial robot, the operator must adjust and operate every time the type or size of the stud changes, not only cannot fully automatic operation of the device be achieved, ,
It also hinders the efficiency of the welding operation. In addition, it is difficult to accurately set the voltage level of the capacitor due to the circuit configuration in the conventional adjustment using the output adjustment knob, so that good welding often cannot be performed.

Therefore, an object of the present invention is to provide an automatic operation type capacitor capable of automatically and accurately setting a charging voltage level of a capacitor according to the type and dimensions of a stud to be welded, thereby enabling fully automatic stud welding. An object of the present invention is to provide a discharge stud welding apparatus.

[Means for Solving the Problems] In order to achieve the above object, according to the first aspect of the present invention, welding energy is stored in a capacitor from an AC power supply through a rectifier circuit, and the stored welding energy is stored in the capacitor. In an automatic operation type capacitor discharge stud welding apparatus in which stud welding is performed by discharging between a stud mounted on a welding gun and a base material, the stud type is connected in parallel to a charging circuit of the capacitor. Different charging voltage levels adapted to and / or dimensions and the type and / or type of stud to be welded
A plurality of charging voltage setting circuits adapted to be selectively operated in accordance with the dimensions, wherein each of the charging voltage setting circuits is turned on / off by a command signal corresponding to the type and / or size of the stud to be welded; It is characterized by having a switching element to be controlled.

According to the second aspect of the present invention, welding energy is accumulated in a capacitor from an AC power supply through a rectifier circuit, and the accumulated welding energy is discharged between a stud mounted on a welding gun and a base material. In an automatic operation type capacitor discharge stud welding apparatus configured to perform stud welding, a charging reference voltage setting circuit connected in parallel to a charging circuit of the capacitor to rapidly charge a capacitor to a certain level, and a charging reference voltage Connected in parallel to the setting circuit to set different charging voltage levels respectively adapted to the type and / or size of the stud, and to selectively operate according to the type and / or size of the stud to be welded. At least one charging voltage setting circuit, wherein each of the charging voltage setting circuits has a type of stud to be welded. It is characterized in that it comprises a switching element on-off controlled by and (or) a command signal corresponding to the dimensions.

[Operation] In the automatic operation type capacitor discharge stud welding apparatus according to the present invention configured as described above, the type and / or type of the stud to be welded is added to the charging circuit of the capacitor.
A plurality of charging voltage setting circuits for setting different charging voltage levels according to the dimensions are connected in parallel, so if the setting value of each charging voltage setting circuit is adjusted accurately in advance, The desired output level can be easily and accurately adjusted by operating the charging voltage setting circuit of the first embodiment. In this case, the setting levels of the charging voltage setting circuits are the same, but the charging voltage setting circuits may have different setting levels if necessary. Further, in the present invention, a switching element which is turned on / off by a command signal corresponding to the type and / or size of the stud to be welded is provided for each charging voltage setting circuit. If programmed in advance with suitable means in accordance with the welding procedure, a power level suitable for the stud gripped by the welding gun mounted on the arm of the industrial robot will automatically be obtained.

Further, by providing the charging reference voltage setting circuit, the capacitor can be rapidly charged to a certain level.

Example An example of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows a circuit configuration of a main part of a capacitor discharge stud welding apparatus according to one embodiment of the present invention.
Is a power supply, 2 is a rectifier circuit composed of four diodes D1 to D4, 3 is a charging voltage setting circuit section connected in parallel to the charging circuit of the capacitor 4, and includes a minimum charging reference voltage setting circuit composed of a variable resistor VR1, and a variable A parallel circuit consisting of a charging voltage setting circuit for a 4 mm diameter stud comprising a resistor VR2, a charging voltage setting circuit for a 5 mm diameter stud comprising a variable resistor VR3, and a charging voltage setting circuit for a 6 mm diameter stud comprising a variable resistor VR4. It is configured. Reference numeral 5 denotes a switching element formed of a thyristor connected to a discharge circuit of the capacitor 4, reference numerals 6 and 7 denote output terminals, and reference numeral 8 denotes an operation control circuit.

In the circuit of FIG. 1, the variable resistor VR1 forming the minimum charging reference voltage setting circuit has three relays CR shown in FIG.
Normally closed contacts CR1-3, CR2-3, CR of each relay in the relay circuit for operating the charging voltage setting circuit section consisting of 1, CR2, CR3
3-3 are connected in series, and the variable resistor VR2 which forms the charging voltage setting circuit for the 4mm diameter stud has the normally open contact CR of the relay CR1.
1-2 are connected in series, and the normally open contact CR of the relay CR2 is connected to the variable resistor VR3 forming the charging voltage setting circuit for the 5mm diameter stud.
2-2 are connected in series, and a normally open contact CR3-2 of a relay CR3 is connected in series to a variable resistor VR4 forming a charging voltage setting circuit for a 6 mm diameter stud.

One of the interlocking switches SW1 to SW3 is connected in series between the normally closed contacts CR1-3, CR2-3, and CR3-3 of the relay connected in series with the variable resistor VR1. The other switch element of the switch is a variable resistor VR2, VR
3 and VR4. These interlocking switches SW1 to SW3 are used when adjusting the resistance values of the respective variable resistors VR2, VR3 and VR4 constituting the respective charging voltage setting circuits in advance. Thus, as shown, one switch element connected in series with the variable resistor VR1 is normally closed, while the other switch elements connected to each of the variable resistors VR2, VR3, VR4 are open. In state.

In the charging voltage setting circuit section operation relay circuit shown in FIG. 2, three normally closed contacts CR4-1 and CR4- of the welding gun trigger relay CR4 shown in FIG.
2 and CR4-3 are connected to each other, and the charging voltage setting command relay circuit shown in FIG. 4 is connected in series with each of these normally closed contacts (this relay circuit comprises three relays CR5, CR6 and CR7). Normally open contacts CR5-1, CR6-1,
CR7-1 is connected to each of these normally open contacts CR5-
1, normally open contacts CR1-1, CR2-1, and CR3-1 for self-holding of the relays CR1, CR2, and CR3 are connected in parallel to CR6-1 and CR7-1, respectively. The operation of the charge voltage setting command relay circuit of FIG. 4 is not shown, but is advantageously performed automatically by the operator presetting the operation mode according to a predetermined program in accordance with the stud welding procedure. To be performed.

Each relay in the relay circuit shown in FIGS. 3 and 4 is designed to operate for about 0.5 second in one operation. In FIG. 1, CR4-4 is a normally open contact of the welding gun trigger relay CR4 in FIG.

To briefly explain the operation of the device configured as described above, first, the capacitor 4 is connected to each of the relays CR1, CR1 in the relay circuit for operating the charging voltage setting circuit section shown in FIG.
2. The variable resistor VR1 of the charging voltage setting circuit 3 through the normally closed contacts CR1-3, CR2-3, CR3-3 of CR3 and one of the normally closed switch elements of the interlocking switches SW1 to SW3.
Is charged to the charging voltage level set by the minimum charging reference voltage setting circuit. Here, when the stud welding is commanded by the operation of relay CR5 of the charging voltage setting command relay circuit shown in FIG. 4 to perform the stud welding with a diameter of 4 mm, the normally open contact CR5-1 of relay CR5 is closed. The relay CR1 in the relay circuit for operating the charging voltage setting circuit shown in FIG. 2 is energized, and as a result, the charging voltage setting circuit for the 4 mm diameter stud composed of the variable resistor VR2 of the charging voltage setting circuit 3 is closed. The capacitor 4 is charged to a charging voltage level determined by the variable resistor VR2, that is, a level suitable for a 4 mm diameter stud. When the gun trigger relay CR4 shown in FIG. 3 is operated in such a state,
The relay CR1 in FIG. 2 is deactivated, the charging voltage setting circuit for the 4 mm diameter stud is opened, and the gun trigger relay is opened.
The normally open contact CR4-4 of CR4 is closed, and as a result, a firing signal is supplied from the operation control circuit 8 to the gate electrode of the thyristor 5 connected to the discharge circuit of the capacitor 4, and the capacitor 4 is connected through the thyristor 5. A discharge is generated from the output terminals 6 and 7 through a stud (not shown) and a base material, and welding is performed.

In this way, the capacitor 4 is charged to the level suitable for the studs of 5 mm and 6 mm via the relay circuit similarly combined, and the desired welding operation can be automatically performed.

It should be noted that the illustrated embodiment is merely an example, and various modifications and changes are possible. For example, depending on the capacity of the capacitor 4, the charging voltage setting circuit may be constituted by three or more or less. Also, the present invention can be appropriately applied to any other capacitor discharge type stud welding circuit device.

[Effects of the Invention] As described above, according to the present invention, a plurality of charging voltage setting circuits for setting different charging voltage levels according to the type and / or size of the stud to be welded are provided for the capacitor. The charging voltage setting circuit is connected in parallel to the charging circuit, and the charging voltage setting circuits are configured to be turned on / off by a command signal corresponding to the type and / or size of the stud to be welded. ) Even if the dimensions change, an appropriate output level can be set without having to manually adjust the output each time, which is extremely useful for fully automatic operation of a stud welding device.
In addition, since the voltage level can be set accurately, it is possible to easily obtain a uniform welding characteristic with no variation.

[Brief description of the drawings]

FIG. 1 is a schematic circuit diagram showing a main part of an automatic operation type capacitor discharge stud welding apparatus embodying the present invention.
FIG. 3 is a schematic circuit diagram showing an example of a relay circuit for operating a charging voltage setting circuit, FIG. 3 is a schematic diagram showing a welding gun trigger relay, and FIG. 4 is a schematic circuit line showing an example of a charging voltage setting command relay circuit. FIG. In the figure, 1: power supply, 2: rectifier circuit composed of four diodes D1 to D4, 3: charging voltage setting circuit section, 4: capacitor, 5: switching element, 6, 7: output terminal, 8: operation control circuit, VR
1, VR2, VR3, VR4: Variable resistor, CR1 to CR7: Relay.

Claims (2)

(57) [Claims] A stud welding is performed by accumulating welding energy in a capacitor from an AC power supply through a rectifier circuit and discharging the accumulated welding energy between a stud mounted on a welding gun and a base material. In an automatically operated capacitor discharge type stud welding apparatus, different charging voltage levels are connected in parallel to the charging circuit of the capacitor, each adapted to the type and / or size of the stud, and the type and And / or a plurality of charging voltage setting circuits adapted to be selectively operated in accordance with the dimensions, wherein each of the charging voltage setting circuits has a command according to the type and / or size of the stud to be welded. Automatically operated capacitor discharge type stud melting characterized by comprising a switching element which is controlled on and off by a signal Apparatus. 2. A welding energy is stored in a capacitor from an AC power supply through a rectifier circuit, and the stored welding energy is discharged between a stud mounted on a welding gun and a base material to perform stud welding. In an automatic operation type capacitor discharge stud welding apparatus, a charging reference voltage setting circuit that is connected in parallel to the capacitor charging circuit and rapidly charges the capacitor to a certain level, and is connected in parallel to the charging reference voltage setting circuit. At least one charging voltage adapted to set different charging voltage levels, each adapted to the type and / or size of the stud, and to selectively operate according to the type and / or size of the stud to be welded. And a setting circuit, wherein each of the charging voltage setting circuits described above determines a type and / or size of a stud to be welded. Automatic operated capacitor charging stud welding apparatus, characterized in that it comprises a switching element on-off controlled by a command signal corresponding to the.