JP2009255161A - Arc spot welding apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an arc spot welding apparatus capable of automatically setting the welding current value Ir and the welding time Tr for forming the workpiece back side nugget diameter Ds capable of obtaining the desired welding strength. <P>SOLUTION: The arc spot welding apparatus for executing the arc welding by running the predetermined welding current to a workpiece 2 formed by superposing a plurality of materials to be welded for the predetermined welding time comprises a plate thickness setting unit AS for setting the plate thickness As of the materials to be welded, a back side nugget diameter setting unit DS for setting the back side nugget diameter Ds of the workpiece 2, a condition table for setting the relationship in advance between the plate thickness As, the back side nugget diameter Ds, the welding current value Ir, and the welding time Tr, and a condition setting unit CS for automatically setting the welding current value Ir and the welding time Tr from the condition table with the set plate thickness As and the set back side nugget diameter Ds as the input. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention provides an arc spot welding apparatus capable of automating the setting of a welding current and a welding time for optimizing the back surface nugget diameter of a workpiece when a workpiece on which a plurality of workpieces are stacked is arc spot welded. It is about.

  In arc spot welding by non-consumable electrode arc such as TIG welding and plasma welding, a nozzle at the tip of the welding torch is pressed against a workpiece on which a plurality of workpieces are stacked, and a predetermined welding current Iw is set to a predetermined welding time Tw. Only the current is applied to generate an arc and the workpiece is welded.

  FIG. 12 is a configuration diagram of a general arc spot welding apparatus. The welding power source PS outputs a welding current Iw and a welding voltage Vw for generating the non-consumable electrode arc 3. Since the welding power source PS has a constant current characteristic, the set welding current Iw is energized, and the welding voltage Vw becomes a value substantially proportional to the arc length. Since arc spot welding is performed, the welding power source PS sets the welding current Iw and the welding time Tw that is the energization time.

  A non-consumable electrode 1 (sometimes simply referred to as an electrode) such as a tungsten electrode is attached to the tip of the welding torch 4, and a nozzle 5 is provided on the outside thereof. Inside the nozzle 5, a shield gas such as argon gas flows. The workpiece 2 is formed by stacking a plurality of materials to be welded.

  In arc spot welding, the workpiece 5 is welded by generating an arc 3 by energizing a predetermined welding current Iw for a predetermined welding time Tw while the nozzle 5 is pressed against the workpiece 2.

  FIG. 13 is a diagram illustrating a welded portion of the workpiece 2 on which the above-described arc spot welding is performed. 1A shows a cross-sectional view, and FIG. 1B shows the back surface of the workpiece 2. As shown in FIG. 2A, a weld metal is formed and joined through two workpieces to be welded. Further, as shown in FIG. 5B, a melted portion having a diameter D (hereinafter referred to as a back surface nugget diameter D) is formed on the back surface. The back surface nugget diameter D greatly affects the bonding strength. Therefore, in order to obtain a desired bonding strength, it is necessary to form an appropriate back surface nugget diameter D. For this purpose, it is necessary to set the welding current Iw and welding time Tw of arc spot welding to appropriate values (see, for example, Patent Documents 1 and 2 as conventional techniques).

JP-A-7-251266 JP-A-5-169262

  As described above, in order to obtain a desired bonding strength, it is necessary to form an appropriate back surface nugget diameter D. For this purpose, it is necessary to set the welding current Iw and the welding time Tw to appropriate values. However, in order to obtain an appropriate back surface nugget diameter D, welding is repeated many times while adjusting the welding current Iw and the welding time Tw for each welding condition such as the material to be welded, the plate thickness, and the number of stacked sheets. You must find the right conditions. For this reason, it took time for production preparation, and the production efficiency was reduced. Furthermore, this condition setting was very difficult for unskilled workers.

  Then, an object of this invention is to provide the arc spot welding apparatus which can make easy the setting of the welding current and welding time for forming an appropriate back surface nugget diameter.

In order to solve the above-described problem, the first invention
In an arc spot welding apparatus for generating an arc between a workpiece and an electrode formed by stacking a plurality of workpieces, and applying a predetermined welding current to the arc for a predetermined welding time for welding,
A plate thickness setting section for setting the plate thickness of the material to be welded;
A back surface nugget diameter setting unit for setting a back surface nugget diameter of the workpiece;
A condition table in which the relationship between the plate thickness and the back surface nugget diameter and the welding current value and the welding time is set in advance,
A condition setting unit that automatically sets the welding current value and the welding time from the condition table with the set plate thickness and the set back surface nugget diameter as inputs;
An arc spot welding apparatus comprising:

In the second invention, the plate thickness is a total value of the plate thicknesses of the workpieces forming the workpiece.
An arc spot welding apparatus according to the first aspect of the invention.

According to a third aspect of the invention, the condition setting unit outputs the welding current value and the welding time from the condition table with the set plate thickness and the set back surface nugget diameter as inputs, and sets both values to the values. Multiplying a coefficient according to the number of workpieces forming the workpiece to correct and set the welding current and the welding time,
An arc spot welding apparatus according to the second aspect of the invention.

4th invention, the electrode-workpiece | work distance setting part which sets the distance of the said electrode and the said workpiece | work,
A correction unit that multiplies the welding time set by the condition setting unit by a coefficient according to the set electrode-workpiece distance; and
The arc spot welding apparatus according to any one of the first to third inventions, further comprising:

5th invention, the electrode-workpiece | work distance setting part which sets the distance of the said electrode and the said workpiece | work,
A correction unit that multiplies the welding current value set by the condition setting unit by a coefficient according to the set electrode-workpiece distance; and
The arc spot welding apparatus according to any one of the first to third inventions, further comprising:

6th invention is equipped with the voltage detection part which detects a welding voltage and outputs a welding voltage detection value,
The electrode / workpiece distance setting unit automatically calculates and sets the electrode-workpiece distance based on the welding voltage detection value,
An arc spot welding apparatus according to the fourth or fifth aspect of the invention.

  According to the first aspect of the present invention, the welding current is obtained from the condition table in which the relation between the plate thickness and the back surface nugget diameter, the welding current value, and the welding time is set with the plate thickness of the workpiece and the back surface nugget diameter of the workpiece as inputs. And the welding time can be output. For this reason, it is possible to automatically set the welding current and the welding time in arc spot welding in which a desired back surface nugget diameter is obtained, and the man-hours necessary for setting the conditions are reduced and the production efficiency is improved. In addition, even an unskilled worker can easily set conditions and improve the operability of the arc spot welding apparatus.

  According to the second invention, by setting the plate thickness in the condition table to the combined thickness value, the welding current and welding can be obtained from one condition table even when the workpiece is formed of a material to be welded having different plate thicknesses. The time can be set automatically. For this reason, the number of condition tables to be set in advance can be reduced, and the condition table creation time is shortened. Furthermore, even when setting conditions for workpieces with different thicknesses, it is only necessary to set the total thickness values, and there is no need to set each thickness, which improves operability in setting conditions.

  According to the third aspect of the invention, the welding current value and the welding time are output from the condition table, and the welding current and the welding time are corrected by multiplying these values by a coefficient corresponding to the number of workpieces forming the workpiece. To set. For this reason, the back surface nugget diameter can be set to a desired value even when the number of sheets to be stacked is different, such as two sheets, three sheets, etc., using the same condition table. Therefore, the number of condition tables to be set in advance can be reduced, and the condition table creation time can be shortened.

  According to the fourth aspect of the present invention, the desired back surface nugget diameter is formed by correcting the welding time set by the method of the first to third aspects of the invention even if the electrode-workpiece distance changes. Can do.

  According to the fifth aspect, even if the electrode-workpiece distance changes, the desired back surface nugget diameter is formed by correcting the welding current value set by the method of the first to third aspects. be able to.

  According to the sixth aspect, the electrode-workpiece distance can be automatically set from the welding voltage detection value. For this reason, in the 4th invention and the 5th invention, it is not necessary to input the electrode-workpiece distance manually, and the operability is improved.

  Embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1]
FIG. 1 is a block diagram of an arc spot welding apparatus according to Embodiment 1 of the present invention. Hereinafter, each block will be described with reference to FIG.

  The power supply main circuit PM receives a commercial power supply such as a three-phase 200V as an input, performs output control such as inverter control according to a drive signal Dv described later, and outputs a welding current Iw and a welding voltage Vw for generating the arc 3. This power supply main circuit PM includes a primary rectifier for rectifying commercial power, a capacitor for smoothing the rectified direct current, an inverter circuit for converting the smoothed direct current to high frequency alternating current, and reducing the high frequency alternating current to a voltage value suitable for arc welding. High-frequency transformer, a secondary rectifier that rectifies the stepped-down high-frequency alternating current, and a reactor that smoothes the rectified direct-current.

  An arc 3 is generated between the non-consumable electrode 1 attached to the tip of the welding torch 4 and the workpiece 2. A nozzle 5 surrounds the non-consumable electrode 1, and the nozzle 5 is pressed against the work 2.

  The material setting circuit MS outputs a material setting signal Ms for setting the material of the material to be welded that forms the workpiece 2. For example, the material setting signal Ms is a signal that is at a high level when the material is stainless steel and a low level when the material is steel. The plate thickness setting circuit AS outputs a plate thickness setting signal As for setting the plate thickness of the material to be welded forming the workpiece 2. For example, the value of the plate thickness setting signal As is a number representing a plate thickness (mm) such as 0.8, 1.0, 1.2, 1.4, or the like. The back surface nugget diameter setting circuit DS outputs a back surface nugget diameter setting signal Ds for setting a desired back surface nugget diameter. For example, the value of the back surface nugget diameter setting signal Ds is a number representing a diameter (mm) such as 1, 2, 3, and the like.

  The condition setting circuit CS has a built-in condition table, and extracts the welding current setting value and the welding time setting value from the condition table with the material setting signal Ms, the plate thickness setting signal As and the back surface nugget diameter setting signal Ds as inputs. Then, the welding current setting signal Ir and the welding time setting signal Tr are output. Details of this condition table will be described later.

  The welding current detection circuit ID detects the welding current Iw and outputs a welding current detection signal Id. The current error amplification circuit EI amplifies an error between the welding current setting signal Ir and the welding current detection signal Id and outputs a current error amplification signal Ei.

  The activation circuit ON is determined by the welding time setting signal Tr when the welding time setting signal Tr is input and a welding start signal St is input from an activation switch (not shown) provided in the welding torch 4 or the like. An activation signal On that becomes High level only for a time is output. While the activation signal On is at a high level, the drive circuit DV performs the pulse width modulation control with the current error amplification signal Ei as an input, and outputs the drive signal Dv.

  FIG. 2 is an example of the condition table described above. The figure shows the case where the material of the workpiece 2 is stainless steel. The figure shows the case where two sheets of the same thickness are welded. In the table, 0.8 to 1.4 mm in the first row indicates the thickness of the material to be welded forming the workpiece 2. Moreover, 1-3 mm of the 1st line shows a back surface nugget diameter. When the material setting signal Ms is high level (stainless steel), the plate thickness setting signal As is 1.0 mm, and the back surface nugget diameter setting signal Ds is 2 mm, welding is performed from this condition table. The value of the current setting signal Ir is 100 A, and the value of the welding time setting signal Tr is 1.5 seconds. In this way, it is possible to automatically set the welding current and the welding time for obtaining a desired back surface nugget diameter.

  FIG. 3 is an example different from FIG. 2 of the condition table described above. The figure shows the case where the material of the workpiece 2 is steel. The figure shows the case where two sheets of the same thickness are welded. In the table, 0.8 to 1.6 mm in the first row indicates the thickness of the material to be welded forming the workpiece 2. Moreover, 1-3 mm of the 1st line shows a back surface nugget diameter. When the material setting signal Ms is at a low level (steel), the plate thickness setting signal As is 1.0 mm, and the back surface nugget diameter setting signal Ds is 2 mm, the welding current is calculated from this condition table. The value of the setting signal Ir is 120A, and the value of the welding time setting signal Tr is 1.5 seconds. In this way, it is possible to automatically set the welding current and the welding time for obtaining a desired back surface nugget diameter.

  In the above, when the material of the workpiece 2 is other than stainless steel or steel, a condition table corresponding to the material is set in advance. Furthermore, when the workpiece 2 is, for example, three sheets other than the two sheets of the welded material, a condition table corresponding to this is set in advance. When the desired nugget diameter is an intermediate value in the table, the welding current and the welding time are set by performing interpolation calculation from the values before and after the table. Interpolation calculation is performed as follows. When the plate thickness is A1 mm and the back surface nugget diameter is d1 mm, the welding current from the table is I1, and the welding time is T1. Further, when the plate thickness is A1 mm and the back surface nugget diameter is D2 mm, the welding current from the table is I1, and the welding time is T2. At this time, the welding current I3 when the plate thickness is A1 mm and the back surface nugget diameter is D3 (D1 <D3 <D2) is set to I3 = (I1 + I2) / 2 to simplify the calculation, and the welding time T3 is T3. = (T1 + T2) / 2. When performing the interpolation calculation more precisely, the welding current and welding time may be calculated by linear interpolation and proportional distribution.

  According to the first embodiment described above, welding is performed from a condition table in which the relationship between the plate thickness and the back surface nugget diameter, the welding current value, and the welding time is set by using the thickness of the workpiece and the back surface nugget diameter of the workpiece as inputs. Current and welding time can be output. For this reason, it is possible to automatically set the welding current and the welding time in arc spot welding in which a desired back surface nugget diameter is obtained, and the man-hours necessary for setting the conditions are reduced and the production efficiency is improved. In addition, even an unskilled worker can easily set conditions and improve the operability of the arc spot welding apparatus.

[Embodiment 2]
The arc spot welding apparatus according to Embodiment 2 of the present invention is different in the condition table structure described above. Therefore, the block diagram is the same as FIG. 1 described above. However, the structure of the condition table built in the condition setting circuit CS is different. Further, in the present embodiment, what is set by the plate thickness setting circuit AS is a total value of the plate thicknesses of a plurality of workpieces forming the workpiece 2. That is, the plate thickness setting signal As sets the plate thickness total value.

  FIG. 4 is a diagram illustrating an example of a condition table according to the present embodiment. This figure corresponds to FIG. The figure shows the case where the material of the welded material is stainless steel.

  In this condition table, the first column represents the total thickness value, and is composed of 1.6, 2.0, 2.4, and 2.8 mm. The first line represents the back surface nugget diameter and is composed of 1, 2, 3 mm. For example, consider a case where the workpiece 2 is a stack of two workpieces having a thickness of 1.0 mm and the back surface nugget diameter is 2 mm. In this case, since the total thickness value is 2.0 mm, the welding current is 100 A from the condition table, and the welding time is 1.5 seconds. These values are output as a welding current setting signal Ir and a welding time setting signal Tr.

  By constructing the condition table with the total thickness values, it is possible to deal with workpieces 2 having different thicknesses. For example, when the workpiece 2 is formed of a workpiece to be welded of 0.8 mm and a workpiece to be welded of 1.2 mm, the total thickness value is 2.0 mm. When the back surface nugget diameter is 2 mm, the welding current is 100 A from the condition table, and the welding time is 1.5 seconds. Thus, even when the workpiece 2 is formed from materials to be welded with different plate thicknesses, one condition table can be used, and the number of condition tables set in advance can be reduced.

  According to the above-described second embodiment, by setting the plate thickness in the condition table to the combined thickness value, the welding current and the current from one condition table can be obtained even when the workpiece is formed from a material to be welded having a different plate thickness. The welding time can be set automatically. For this reason, the number of condition tables to be set in advance can be reduced, and the condition table creation time is shortened. Furthermore, even when setting conditions for workpieces with different thicknesses, it is only necessary to set the total thickness values, and there is no need to set each thickness, which improves operability in setting conditions.

[Embodiment 3]
FIG. 5 is a block diagram of an arc spot welding apparatus according to Embodiment 3 of the present invention. This figure corresponds to FIG. 1 described above, and the same reference numerals are given to the same blocks and their explanations are omitted. In the figure, a number setting circuit NS and a correction circuit HC indicated by broken lines are added. Hereinafter, points different from FIG. 1 will be described with reference to FIG.

  The plate thickness setting circuit AS outputs a plate thickness setting signal As for setting the total plate thickness value as in the second embodiment. The condition table built in the condition setting circuit CS is the same as that in FIG. 3 described above, and the welding current setting signal Ir and the welding time setting signal Tr are input to the correction circuit HC. The sheet number setting circuit NS outputs a sheet number setting signal Ns for setting the number of sheets to be welded forming the workpiece 2. The correction circuit HC receives the welding current setting signal Ir, the welding time setting signal Tr, and the number setting signal Ns, and sets the coefficient K determined according to the value of the number setting signal Ns to the value of the welding current setting signal Ir and the welding time. Correction is performed by multiplying the value of the setting signal Tr, and a welding current correction setting signal Ihr and a welding time correction setting signal Thr are output. The welding current correction setting signal Ihr is input to the current error amplification circuit EI, and the welding time correction setting signal Thr is input to the starting circuit ON. That is, Ihr = K · Ir and Thr = K · Tr. The coefficient K varies depending on the value of the number setting signal Ns. For example, the coefficient K = 1.0 when the number setting signal Ns = 2 (two sheets overlap), and the coefficient K = 0.9 when the number setting signal Ns = 3 (three sheets overlap). The reason for the correction is as follows. That is, even if the total thickness value is 2.4 mm, when two sheets are stacked, a 1.2 mm work piece is stacked, and when three sheets are stacked, a 0.8 mm work piece is used. Three sheets are stacked. Even if the total thickness value is the same, the back surface nugget diameter will not be the same unless the welding current and welding time are reduced as the number of stacked sheets increases. For this reason, this correction is performed by a coefficient K corresponding to the number of overlapped sheets. The coefficient K may be set to a different value depending on the welding current and the welding time.

  According to the third embodiment described above, the welding current value and the welding time are output from the condition table, and the welding current and the welding time are corrected by multiplying these values by a coefficient corresponding to the number of workpieces forming the workpiece. And set. For this reason, the back surface nugget diameter can be set to a desired value even when the number of sheets to be stacked is different, such as two sheets, three sheets, etc., using the same condition table. Therefore, the number of condition tables to be set in advance can be reduced, and the production preparation time is shortened.

[Embodiment 4]
FIG. 6 is a block diagram of an arc spot welding apparatus according to Embodiment 4 of the present invention. This figure corresponds to FIG. 1 described above, and the same reference numerals are given to the same blocks and their explanations are omitted. In the figure, an electrode / workpiece distance setting circuit LR indicated by a broken line and a time correction circuit THC indicated by a broken line are added. Hereinafter, points different from FIG. 1 will be described with reference to FIG.

  The electrode / work distance setting circuit LR sets the distance between the non-consumable electrode 1 and the work 2 and outputs an electrode / work distance setting signal Lr. The time correction circuit THC receives the electrode / workpiece distance setting signal Lr and the welding time setting signal Tr as inputs, and the time correction coefficient Kt (%) determined according to the value of the electrode / workpiece distance setting signal Lr and the above-described time correction circuit THC. Is multiplied by the welding time setting signal Tr, and a welding time correction setting signal Thr is output to the start-up circuit ON. The relationship between the value of the electrode / workpiece distance setting signal Lr and the time correction coefficient Kt is illustrated in FIG. On the other hand, the welding current setting signal Ir output from the condition setting circuit CS is directly input to the current error amplifier circuit EI without being corrected.

  FIG. 7 is a diagram illustrating the relationship between the electrode / workpiece distance setting signal Lr and the time correction coefficient Kt. In the figure, the horizontal axis represents the electrode-workpiece distance setting signal Lr (mm), and the vertical axis represents the time correction coefficient Kt (%). As shown in the figure, Kt = 100% when Lr = 2 mm, and Kt = 75% when Lr = 1.5 mm. The welding time correction setting signal Thr is calculated by multiplying the time correction coefficient Kt by the welding time setting signal Tr.

  In the above, the reason for correcting the welding time is as follows. That is, when the distance between the electrode and the workpiece changes, the welding time for forming the same back surface nugget diameter also changes. Although the fourth embodiment is based on the first embodiment, the same applies to the second and third embodiments. When based on the third embodiment, the output signal of the correction circuit HC of FIG. 5 is input to the time correction circuit THC of FIG.

  According to the fourth embodiment described above, a desired back surface nugget diameter is formed by correcting the welding time set by the method of the first to third embodiments even if the distance between the electrode and the workpiece changes. Can do.

[Embodiment 5]
FIG. 8 is a block diagram of an arc spot welding apparatus according to Embodiment 5 of the present invention. This figure corresponds to FIG. 6 described above, and the same reference numerals are given to the same blocks, and their description is omitted. In the figure, the time correction circuit THC in FIG. 6 is replaced with a current correction circuit IHC indicated by a broken line. Hereinafter, points different from FIG. 6 will be described with reference to FIG.

  The current correction circuit IHC receives the electrode / workpiece distance setting signal Lr and the welding current setting signal Ir as inputs, and determines the current correction coefficient Ki (%) determined according to the value of the electrode / workpiece distance setting signal Lr and the above-described value. The value of the welding current setting signal Ir is multiplied and the welding current correction setting signal Ihr is output to the current error amplification circuit EI. The relationship between the value of the electrode-workpiece distance setting signal Lr and the current correction coefficient Ki is illustrated in FIG. On the other hand, the welding time setting signal Tr output from the condition setting circuit CS is directly input to the activation circuit ON without being corrected.

  FIG. 9 is a diagram illustrating the relationship between the electrode / workpiece distance setting signal Lr and the current correction coefficient Ki. In the figure, the horizontal axis represents the electrode-workpiece distance setting signal Lr (mm), and the vertical axis represents the current correction coefficient Ki (%). As shown in the drawing, Ki = 100% when Lr = 2 mm, and Ki = 75% when Lr = 1.5 mm. The welding current correction setting signal Ihr is calculated by multiplying the welding current setting signal Ir by the current correction coefficient Ki.

  In the above, the reason for correcting the welding current is as follows. That is, when the distance between the electrode and the workpiece changes, the welding current for forming the same back surface nugget diameter also changes. The fifth embodiment is based on the first embodiment, but the same applies to the second and third embodiments. When based on the third embodiment, the output signal of the correction circuit HC in FIG. 5 is input to the current correction circuit IHC in FIG.

  According to the fifth embodiment described above, a desired back surface nugget diameter is formed by correcting the welding current set by the method of the first to third embodiments even if the electrode-workpiece distance changes. Can do.

[Embodiment 6]
FIG. 10 is a block diagram of an arc spot welding apparatus according to Embodiment 6 of the present invention. This figure corresponds to FIG. 6 described above, and the same reference numerals are given to the same blocks, and their description is omitted. In the figure, the electrode / workpiece distance setting circuit LR in FIG. 6 is replaced with a second electrode / workpiece distance setting circuit LR2 indicated by a broken line, and a welding voltage detection circuit VD indicated by a broken line is added. Hereinafter, points different from FIG. 6 will be described with reference to FIG.

  The welding voltage detection circuit VD detects the welding voltage Vw between the non-consumable electrode 1 and the base material 2 and outputs a welding voltage detection signal Vd. As will be described later with reference to FIG. 11, since the value of the welding voltage detection signal Vd and the electrode-workpiece distance (arc length) are correlated, the electrode-workpiece distance is detected based on the value of the welding voltage detection signal Vd. can do. The second electrode / workpiece distance setting circuit LR2 receives the welding voltage detection signal Vd as an input, calculates an electrode / workpiece distance according to a predetermined voltage distance conversion function, and outputs an electrode / workpiece distance setting signal Lr. To do.

  FIG. 11 is a diagram illustrating the voltage distance conversion function described above. In the figure, the horizontal axis represents the welding voltage detection signal Vd (V), and the vertical axis represents the electrode-workpiece distance setting signal Lr (mm). From this figure, the value of the electrode-workpiece distance setting signal Lr corresponding to the value of the welding voltage detection signal Vd is calculated.

  In the above description, the case where the electrode-workpiece distance setting signal Lr is set based on the welding voltage detection signal Vd based on the fourth embodiment has been described, but the same applies to the fifth embodiment.

  According to the above-described sixth embodiment, the distance between the electrode and the workpiece can be automatically set from the welding voltage detection value. For this reason, in Embodiment 4 and Embodiment 5, it is not necessary to manually input the distance between the electrode and the workpiece, and the operability is improved.

It is a block diagram of the arc spot welding apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows an example of the condition table incorporated in the condition setting circuit CS in FIG. It is a figure which shows an example different from FIG. 2 of the condition table incorporated in the condition setting circuit CS in FIG. It is a figure which shows an example of the condition table in the arc spot welding apparatus which concerns on Embodiment 2 of this invention. It is a block diagram of the arc spot welding apparatus which concerns on Embodiment 3 of this invention. It is a block diagram of the arc spot welding apparatus which concerns on Embodiment 4 of this invention. FIG. 7 is a diagram illustrating a relationship between an electrode / workpiece distance setting signal Lr built in the time correction circuit THC of FIG. 6 and a time correction coefficient Kt. It is a block diagram of the arc spot welding apparatus which concerns on Embodiment 5 of this invention. FIG. 9 is a diagram illustrating a relationship between an electrode / workpiece distance setting signal Lr and a current correction coefficient Ki built in the current correction circuit IHC of FIG. 8; It is a block diagram of the arc spot welding apparatus which concerns on Embodiment 6 of this invention. It is a figure which illustrates the voltage distance conversion function incorporated in the 2nd electrode-workpiece | work distance setting circuit LR2 of FIG. It is a block diagram of the arc spot welding apparatus of a prior art. It is a figure which shows the welding part by arc spot welding.

Explanation of symbols

1 Non-consumable electrode 2 Work piece 3 Arc 4 Welding torch 5 Nozzle AS Plate thickness setting circuit As Plate thickness setting signal CS Condition setting circuit D Back surface nugget diameter DS Back surface nugget diameter setting circuit DS Back surface nugget diameter setting signal DV Drive circuit Dv Drive signal EI Current error amplification circuit Ei Current error amplification signal HC correction circuit I1-I3 Welding current ID Welding current detection circuit Id Welding current detection signal IHC Current correction circuit Ihr Welding current correction setting signal Ir Welding current setting signal Iw Welding current K factor Ki Current correction Coefficient Kt Time correction coefficient LR Electrode / workpiece distance setting circuit Lr Electrode / workpiece distance setting signal LR2 Second electrode / workpiece distance setting circuit MS Material setting circuit Ms Material setting signal NS Number setting circuit Ns Number setting signal ON Start circuit On start signal PM power supply main circuit PS welding power supply St welding start signal T1 ~ 3 Welding Time THC time correction circuit Thr welding time correction setting signal Tr welding time setting signal Tw welding time VD welding voltage detection circuit Vd welding voltage detection signal Vw welding voltage

Claims (6)

In an arc spot welding apparatus for generating an arc between a workpiece and an electrode formed by stacking a plurality of materials to be welded, and energizing and welding a predetermined welding current to the arc for a predetermined welding time,
A plate thickness setting section for setting the plate thickness of the material to be welded;
A back surface nugget diameter setting unit for setting a back surface nugget diameter of the workpiece;
A condition table in which the relationship between the plate thickness and the back surface nugget diameter and the welding current value and the welding time is set in advance,
A condition setting unit that automatically sets the welding current value and the welding time from the condition table with the set plate thickness and the set back surface nugget diameter as inputs;
An arc spot welding apparatus comprising: The plate thickness is a total value of the plate thicknesses of the workpieces forming the workpiece,
The arc spot welding apparatus according to claim 1. The condition setting unit outputs the welding current value and the welding time from the condition table with the set plate thickness and the set back surface nugget diameter as inputs, and forms the workpiece on both values. Set by correcting the welding current and the welding time by multiplying by a coefficient according to the number of materials,
The arc spot welding apparatus according to claim 2. An electrode / workpiece distance setting unit for setting a distance between the electrode and the work;
A correction unit that multiplies the welding time set by the condition setting unit by a coefficient according to the set electrode-workpiece distance; and
The arc spot welding apparatus according to claim 1, further comprising: An electrode / workpiece distance setting unit for setting a distance between the electrode and the work;
A correction unit that multiplies the welding current value set by the condition setting unit by a coefficient according to the set electrode-workpiece distance; and
The arc spot welding apparatus according to claim 1, further comprising: It has a voltage detector that detects the welding voltage and outputs the welding voltage detection value.
The electrode / workpiece distance setting unit automatically calculates and sets the electrode-workpiece distance based on the welding voltage detection value,
The arc spot welding apparatus according to claim 4 or 5, wherein

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