JP2003154460A - Welding equipment of stud - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve so as to more stably obtain a high quality welding condition and to reduce costs relating to the setting operation of a welding current value by contriving automation of the setting operation of the value of welding current flowing during stud welding, without depending on an operator's experience alone. SOLUTION: The equipment is provided with a storage means 35 in which an allowable range concerning a short-circuit current Ic in the case of preliminary contact and energization between a stud 24 and a base material 26 is stored correspondingly to the diameter D of the stud, a discrimination means (CPU33) in which the short-circuit current Ic obtained by checking the short- circuit energization is inputted and discriminated whether the current is within the allowable range, a means for instructing to recheck which, in the case where the short-circuit current Ic is discriminated as outside the allowable range, instructs to adjust the external characteristics of the welding machine and to recheck the short-circuit energization, and a means for instructing to start welding in the case where the short-circuit current Ic obtained by checking the short-circuit energization is discriminated as within the allowable range by the discrimination means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding apparatus for welding a stud to a base material by a submerged arc press welding method (abbreviated as SAP welding method) or an arc stud welding method.

[0002]

2. Description of the Related Art FIG. 8 is a structural conceptual view showing an example of a general welding apparatus conventionally used for welding studs. In the figure, 1 is an AC or DC welding machine. Generally, an AC welding machine is used for the SAP welding method, and a DC welding machine is used for the arc stud welding method. As shown in the drawing, the welding machine 1 is connected to the welding cables 4 and 5 connected to the welding gun 3 via the control device 2 and the grounding side cable 7 connected to the base material 6, and these are connected. It constitutes the welding current supply circuit. When using a DC welding machine, the positive side is connected to the grounding side cable 7 connected to the base material 6, and the negative side is connected to the welding cables 4 and 5 connected to the welding gun 3. Further, the control device 2 is connected to the welding machine 1 via the control cable 8, the welding gun 3 via the control cable 9, and the operation section 11 via the control cable 10. The operation unit 11 is provided with a welding start button, an emergency stop button, etc., and the control device 2
The operation of the welding gun 3 is controlled based on the operation command from the operation unit 11. Then, when the welding start button of the operation unit 11 is pressed, the supply of the welding current to the welding gun 3 is started through the welding current supply circuit, and the stud 12 held by the welding gun 3 and the base material 6 are separated from each other. Arc welding will be started. During that time, the control unit 2 measures the elapsed time, and when the set time has elapsed, the stud 12 is pushed into the molten metal on the base metal 6 side,
The supply of the welding current is stopped and the welding process for the stud is completed. A welding time change dial is installed in the control device 2 so that the welding time can be adjusted.

FIG. 9 is an external characteristic diagram illustrating the external characteristics of a welding machine generally used in the SAP welding method. Also,
FIG. 10 is an external characteristic diagram illustrating the external characteristics of a welding machine generally used in the arc stud welding method. The external characteristics are illustrated by taking the output voltage on the vertical axis and the output current on the horizontal axis, respectively. In the figure, characteristic curves A to C or D to
F shows an example of the state of change regarding the characteristic curve when the external characteristic is adjusted in each welding machine. When adjusting the set current value on the welding machine side, the above external characteristics are adjusted.
For example, in the case of increasing the welding current value while maintaining the same arc voltage value, the external characteristics of the welding machine are set to the characteristic curve A,
It is possible by shifting from D to C, F side.
It should be noted that this welding current value adjustment operation is generally performed by adjusting the set current value in an appearance in the output current value setting unit provided in the welding machine 1 in appearance. From a practical point of view, this is nothing but the adjustment of the output current value through the adjustment of the external characteristics of the welding machine.

By the way, the external characteristics of a welding machine, in particular, the external characteristics illustrated in FIG. 9 have drooping characteristics that deviate considerably from the ideal constant current characteristics, so that when the external resistance and impedance values change. However, the output current value, that is, the welding current value will change. Therefore, the welding current value supplied to the welding gun 3 shown in FIG. 8 is the welding cable 4, which is connected to the welding gun 3 via the control device 2.
5 and the grounding side cable 7 connected to the base material 6 will be affected by fluctuations in the resistance value and impedance value of the welding current supply circuit. That is, the length of the welding cables 4 and 5, the resistance value change due to the heat generation of the welding cables 4 and 5 themselves due to the welding current or the influence of the outside air temperature, or U formed in the middle of the welding cables 4 and 5.
The welding current fluctuates greatly due to the influence of the inductance due to the slack in the shape of a letter or a loop, and the actual welding current values Ia and Ib greatly differ from the set current value on the welding machine 1 side.

Incidentally, for example, when a stud made of a reinforcing bar having a diameter of about 30 mm is SAP-welded by using an AC welding machine, a fluctuation of several hundred amperes may occur depending on the drooping characteristic of the welding machine. It has been experimentally confirmed that it is not unusual. Similarly, when performing arc stud welding using a DC welding machine, it has been experimentally confirmed that fluctuations of about several tens of amps are not uncommon. The fluctuations in the actual welding current values Ia and Ib as described above also affect the welding result, and the necessary arc state cannot be obtained due to the excess or deficiency of the welding current, which causes the deterioration of the welding quality. For this reason, in order to avoid the deterioration of the welding quality in the field, a method of adjusting the output current value on the welding machine side while observing the welding state based on the experience of the operator is used. However,
With such an empirical method, it is extremely difficult to accurately adjust the welding current values Ia and Ib, and individual differences among workers are increased, and it is technically possible to stably maintain a high quality welding state. It was difficult. Further, the cost of studs and the like used when performing test welding in order to observe the welding state cannot be ignored.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional technical situation, and the welding current value Ia in welding of studs can be obtained without depending only on the experience of the operator. The purpose is to automate the setting work of Ib, improve it so that a good welding condition can be obtained more stably, and reduce the cost required for the setting work of the welding current values Ia and Ib. is there.

[0007]

In order to solve the above-mentioned problems, the present invention has carried out a number of experiments repeatedly, and as a result, the stud diameter D and the welding current value I actually flowing during welding have been found.
It has been clarified that there is a correlation between a and Ib as shown in FIGS. 3 and 4 regarding whether or not a good welding result is stably obtained. That is, FIG. 3 shows the case of the SAP welding method based on the experimental results, and Ia = 20D
(Note that Ia is a numerical value that represents the welding current value in the SAP welding method in amperes, and D is a numerical value that represents the diameter of the stud in mm.) And Ia = Between the upper limit allowable welding current value line Ha indicated by 32D, the allowable range Ja of the welding current value Ia in the SAP welding method in which a good welding result is stably obtained according to the diameter D of the stud is shown. By the way,
When the welding current value Ia is outside the permissible range Ja, it is difficult to stably obtain good quality welding results, no matter how much the welding time or the like is adjusted. That is, when the welding current value Ia is lower than the lower limit allowable welding current value line Ga, the arc state required for the diameter D of the stud cannot be obtained, so that a good welding result cannot be stably obtained. . On the contrary, when the welding current value Ia is higher than the upper limit allowable welding current value line Ha, the arc state becomes excessive with respect to the diameter D of the stud, and similarly, a good welding result can be stably obtained. I couldn't. Also, FIG.
Shows the case of the arc stud welding method based on the experimental result, and the lower limit shown by Ib = 54D (where Ib is the numerical value representing the welding current value in the arc stud welding method in amperes). Allowable welding current value line Gb
And the upper limit allowable welding current value line Hb represented by Ib = 90D, the allowable range Jb of the welding current value Ib in the arc stud welding method in which a good welding result is stably obtained according to the diameter D of the stud. Is shown.

Further, the difference between the arc voltage value between the stud and the base material during welding and the short-circuit voltage value between the stud and the base material when the stud and the base material are energized while being energized is obtained in advance. , A short circuit current value Ic when current is applied in a state where the stud and the base material are in contact with each other is measured, and a voltage value higher than the short circuit current value Ic by a difference between the voltage values is obtained on the external characteristic curve of the welding machine. If the corresponding current value is obtained, the welding current value Ia,
It was confirmed experimentally that it can be almost exactly guessed as Ib. That is, for example, in the welding work by SAP welding, as shown in the enlarged explanatory view of FIG. 5, the case where the external characteristic at that time is set as the characteristic curve B of FIG. 9 will be described as an example. Assuming that the measured short-circuit current value is Ic, first, a point Pc on the characteristic curve B where the output current value corresponds to Ic is obtained, and then the output voltage value is previously measured and the arc voltage value Va is obtained from the point Pc. If a point Pa on the characteristic curve B corresponding to an output voltage value higher by the difference Va-Vc obtained by subtracting the short-circuit voltage value Vc from the point Pa is obtained and the output current value Ia at the point Pa is read, the current value Ia is short-circuited. It can be inferred that the welding current value corresponds to the case where the current value is Ic. By the way, in the case of the SAP welding method, generally, the short circuit voltage value is 5V and the arc voltage value is 4V.
The voltage difference is about 0 V, and the difference between the voltage values is higher by about 35 V for the arc voltage value. Similarly, in the case of the arc stud welding method, the short circuit voltage value is generally 5V and the arc voltage value is about 30V, and the difference between these voltage values is
The arc voltage value is higher by about 25V. The magnitude of the difference between the short-circuit voltage and the arc voltage varies depending on the case, but shows a fairly stable value. Therefore, for example, the allowable ranges Ja, Jb regarding the welding current values Ia, Ib are back-calculated to obtain the allowable ranges Ja,
Short circuit current value Ic corresponding to welding current values Ia and Ib of Jb
By obtaining the range of, it is possible to obtain the allowable range as the short circuit current value Ic.

Further, according to the diameter D [mm] of the stud, Ia = 26D [A] shown as a lower resetting necessity division line La and Ia shown as an upper resetting necessity division line Ma in FIG. If the range of the short-circuit current value Ic corresponding to the reset unnecessary area Na between = 30D [A] is obtained, another allowable range for the short-circuit current value Ic in the case of the SAP welding method can be obtained. The lower resetting necessity division line La and the upper resetting necessity division line Ma predict the normal fluctuation width of the welding current value Ia due to the fluctuation of the resistance value or the impedance value of the welding current supply circuit, If the welding current value Ia is within the reset unnecessary area Na, it is set so as to be within the allowable range Ja even if normal fluctuation occurs. Therefore, if another allowable range for the short-circuit current value Ic is adopted, it is possible to prevent the welding current value Ia from going out of the allowable range Ja due to normal fluctuation. Similarly, the stud diameter D [m
m]], a reset between Ib = 72D [A] shown as the lower reset necessity division line Lb and Ib = 84D [A] shown as the upper reset necessity division line Mb in FIG. If the range of the short circuit current value Ic corresponding to the setting unnecessary region Nb is obtained, it is possible to obtain another allowable range for the short circuit current value Ic in the case of the arc stud welding method. In the short circuit energization check in which the stud and the base material are in contact with each other, the stud or the like is hardly damaged. Therefore, even if any allowable range for the short-circuit current value Ic is adopted, the short-circuit current value Ic measured while repeating the short-circuit energization check as necessary.
By adjusting the external characteristics of the welding machine 1 so that the welding current falls within the allowable range, the desired welding current values Ia and Ib can be obtained more accurately without damage to the studs and the like.

According to the invention of claim 1, the above short circuit current value I
Focusing on the relationship between c and the welding current values Ia and Ib, as a stud welding device, a short-circuit current value Ic when current is applied in a state where the stud and the base material are in contact with each other in advance corresponding to the diameter D of the stud. The short-circuit current value Ic obtained by executing the short-circuit energization check in which the stud and the base material are energized in a state in which the allowable range is calculated and stored, and the short-circuit current value Ic is the above-mentioned Judging means for judging whether the short-circuit current value Ic corresponding to the diameter D of the stud stored in the storage means is included in the allowable range, and the judging means judges that the short-circuit current value Ic is outside the allowable range. In the case where the short-circuit energization check is performed, the re-check instruction means for instructing to adjust the external characteristics of the welding machine to perform the short-circuit energization check again and the short-circuit current value Ic obtained by the short-circuit energization check are determined by the determination means. When the it is determined to be included in the allowable range, it is in a fitted manner of starting welding, i.e. employing the technical means that comprises a welding start instruction means for instructing the start of welding. If the stud welding apparatus according to the present invention is used, the short circuit current value Ic obtained by the short circuit energization check is obtained.
By manually or automatically inputting into the judging means, the short-circuit energization check is performed again when it is judged to be outside the allowable range for the short-circuit current value Ic stored in advance in the storage means. Is instructed and a welding start instruction is issued when it is determined that the welding current values Ia and Ib are within the desired range. Can be paid to. Therefore, a more stable welding state can be easily and accurately obtained. Moreover, as described above, since damage to the studs or the like hardly poses a problem in the short-circuit energization check, the desired welding current values Ia and Ib can be obtained without the trouble and cost of replacing the studs.

In the invention of claim 2, the short circuit current value Ic
The welding current values Ia and Ib corresponding to the short-circuit current value Ic included in the tolerance range according to the stud diameter D [mm] are Ia in the case of the SAP welding method.
= 26D to 30D [A], and in the case of the arc stud welding method, a technical means of setting to satisfy Ib = 72D to 84D [A] was adopted. According to the present invention, even if the welding current values Ia and Ib are subjected to normal fluctuations due to the resistance value and the impedance value of the welding current supply circuit, the welding current values Ia and Ib are out of the allowable ranges Ja and Jb. Things are avoided. According to the invention of claim 3, the arc voltage during the arc welding is compared with the optimum arc voltage corresponding to the optimum arc length for the diameter D [mm] of the stud, which is stored in the storage means in advance, and the arc voltage is distributed to the welding gun. The technical means of providing an arc length control means for outputting an operation command to the installed servo mechanism is adopted. According to the present invention, the optimum arc length is automatically obtained for the diameter D [mm] of the stud, and a better welded state can be accurately obtained.

According to the invention of claim 4, the welding current values Ia and Ib measured during the welding are input and the welding current values Ia and Ib are stored in correspondence with the diameter D [mm] of the stud. Judging means for judging whether the current values Ia, Ib are within the allowable range, and external characteristics of the welding machine when the welding current values Ia, Ib measured by the judging means are judged to be outside the allowable range. The technical means of having an external characteristic monitoring means for indicating the necessity of readjustment was adopted. According to the present invention, the welding current values Ia and Ib are actually measured, and a check is further added as to whether the welding current values Ia and Ib are included in the allowable ranges Ja and Jb as the welding current values Ia and Ib. Since it is configured to indicate the necessity of readjustment with respect to, it is possible to more reliably maintain a good welding state. Further, in the invention of claim 5, when the welding current values Ia and Ib measured by the determination means are determined to be outside the allowable range for the welding current values Ia and Ib, the welding current values Ia and Ib are provided on the welding machine side. The technical means of adopting an external characteristic adjusting means for outputting an operation command to the external characteristic adjusting mechanism is adopted. According to the present invention, the readiness of the external characteristics of the welding machine is automatically adjusted by the judgment means judging that it is out of the allowable range, so that the convenience of the welding apparatus is further improved.

According to the invention of claim 6, the elapsed time from the start of welding is measured, and when the elapsed time reaches the optimum welding time for the diameter D [mm] of the stud previously stored in the storage means, The technical means is adopted which comprises a welding time management means for outputting a downward movement command to the servo mechanism arranged in the welding gun. According to the present invention, since the welding time is automatically controlled to the optimum welding time for the diameter D [mm] of the stud, a good welding result can be obtained. Further, in the invention of claim 7, when the downward movement command is output from the welding time management means to the servomechanism, the position at which the stud comes into contact with the molten metal on the base material or the vicinity thereof is fast. A technical means of instructing to move down and then to move down to a predetermined position in the molten metal at a slow speed was adopted. According to the present invention, it is possible to prevent the molten metal from scattering due to the pushing of the stud, and more quickly push the stud into the molten metal to prevent the deterioration of the welding quality due to the temperature decrease.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention can be widely applied as a stud welding method employing the SAP welding method or the arc stud welding method. Regarding the means for measuring the short-circuit current value Ic or the welding current values Ia, Ib, a welding machine, a welding gun or the vicinity thereof, or an ammeter provided in the controller may be used, or a portable ammeter may be used. May be. If the current value is measured with the welding gun set at the welding position, the specific situation where the welding current supply circuit between the welding machine and the welding gun is placed at the welding position. The short circuit current value Ic or the welding current value I is absorbed in a form that absorbs the influence on the current value below.
It is extremely effective because a and Ib can be measured. Regarding the difference between the arc voltage value between the stud and the base metal during welding and the short circuit voltage value between the stud and the base metal when the stud and the base metal are energized, see The voltage value may be directly measured and compared and calculated, or the voltage value between the output terminals of the welding machine may be measured and compared and calculated.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a main part of a first embodiment of the present invention. In the figure, 21 is an AC or DC welding machine. Generally, an AC welding machine is used in the case of the SAP welding method, and a DC welding machine is used in the case of the arc stud welding method. As shown in the figure, the welding machine 21 is connected to the stud 24 set on the welding gun 23 via the welding cable 22 and to the base material 26 via the ground side cable 25. It constitutes the welding current supply circuit. The welding machine 21 is connected to a control circuit 28 via a control cable 27, and is configured to execute operation control of the welding machine 21 based on a control signal from the control circuit 28. Further, the control circuit 28 is configured to control the pushing mechanism 30 installed in the welding gun 23 via the control cable 29, and the clamp means 31 is moved downward to move the stud 24 to the molten metal on the base metal 26 side. It is configured to be pushed in. Incidentally, reference numeral 32 in the drawing denotes an operation unit, on which a welding start button, an emergency stop button, etc. are installed.

Next, the characteristic part of this embodiment will be described. As shown, the control circuit 28 includes a CPU 33.
Is incorporated into the CPU 33, and the setting means 3 is included in the CPU 33.
4, storage means 35, display means 36, etc. are connected.
Further, the CPU 33 is connected to the voltage detecting means 37 and the current detecting means 38, and short-circuit voltage value Vc or arc voltage values Va and Vb between the stud 24 and the base material 26,
The short-circuit current value Ic or the welding current values Ia and Ib are input. In this embodiment, the short-circuit voltage value Vc or the arc voltage values Va, Vb actually measured by the voltage detection means 37 can be displayed through the display means 36, so that they correspond to the welding current values Ia, Ib. This is convenient for obtaining the difference between the arc voltage value and the short-circuit voltage value required when obtaining the short-circuit current value Ic, but it is not always necessary. Then, the calculation result from the CPU 33 is output as a control signal to the welding machine 21 via the control cable 27, and is output as a control signal to the pushing mechanism 30 via the control cable 29. In the figure, 39 and 40 are A / D converters,
41 is a D / A converter.

In the present embodiment, the short circuit current value Ic corresponding to the diameter D of the stud 24 is previously stored in the storage means 35.
It is necessary to obtain and store a permissible range for. The allowable range for the short-circuit current value Ic in this case is, as described above, back calculated from the allowable ranges Ja, Jb for the welding current values Ia, Ib, and the welding current values Ia, Ia, included in the allowable ranges Ja, Jb. In the case of the SAP welding method, Ia = 26D to 30D depending on the range of the short circuit current value Ic found corresponding to Ib and the diameter D [mm] of the stud.
[A], Ib = 72D in case of arc stud welding method
It is possible to adopt the range of the short-circuit current value Ic obtained corresponding to the welding current values Ia and Ib satisfying ~ 84D [A]. As the short circuit current value Ic corresponding to the welding current values Ia and Ib, the difference Va-Vc obtained by subtracting the short circuit voltage value Vc from the arc voltage value Va and the characteristic curve relating to the external characteristic of the welding machine 21 are used as described above. Can be asked. In this case, the short circuit current value Ic corresponding to the welding current values Ia and Ib
Is often affected by changes in the characteristic curve related to the external characteristics of the welder 21, so it is also effective to set and store a plurality of allowable ranges according to the changes in the characteristic curve. Regarding the specific storage form of the allowable range for the short-circuit current value Ic in the storage unit 35, what kind of storage is possible as long as it is possible to compare the measured short-circuit current value Ic to determine the inside or outside of the allowable range. It may be in the form.

In the welding work using the welding apparatus according to this embodiment, the stud 24 and the base metal 26 are first brought into contact with each other to carry out a short circuit energization check, and the current detecting means 3 is connected.
8, the short-circuit current value Ic at that time is measured and the CPU
Enter in 33. At this time, the CPU 33 functions as the determination unit, and calls the allowable range for the short circuit current value Ic from the storage unit 35 to measure the short circuit current value Ic.
It is determined whether or not it is included in the allowable range by comparing with.
As a result, when it is determined that the short circuit current value Ic is out of the allowable range, an instruction is issued via the display means 36 to adjust the external characteristics of the welding machine and perform the short circuit energization check again. That is, in this case, the CPU 33 and the display means 36 work together to function as a recheck instruction means. When this recheck instruction is issued, the external characteristics of the welding machine 21 are readjusted and the short circuit energization check is executed again. While the recheck instruction is issued, the readjustment of the external characteristics of the welding machine 21 and the short circuit energization check are repeated. In the readjustment of the external characteristics of the welding machine 21, the welding current values Ia, I
The frequency of resetting can be reduced by adjusting in accordance with the set target current value lines Ka and Kb shown in FIGS. 3 to 4, which are set in consideration of the tendency of fluctuation of b.

Next, when the short-circuit current value Ic obtained by the short-circuit energization check is judged by the CPU 33 as the judgment means to be within the allowable range, the display means 3
It is indicated via 6 that the welding is in the starting condition.
That is, in this case, the CPU 33 and the display means 36 work together to function as welding start instruction means.
When the above welding start instruction is issued, the welding start button of the operation unit 32 is pressed to start welding. As a result, the welding cable 21
The welding current values Ia and Ib are supplied between the stud 24 and the base material 26 via the cable 2 and the grounding side cable 25. In this case, since the above-described short circuit energization check has been performed, the desired welding current values Ia and Ib are supplied, and a good welding state can be obtained accurately. When the elapsed time from the start of welding, which is separately timed by the CPU 33 or the like, reaches the welding time stored in the storage means 35 or the like according to the diameter D of the stud 24, the control cable 27 is used. Welding machine 21
To stop the output by sending an output stop signal to
A pushing signal is transmitted to the pushing mechanism 30 via the control cable 29 to move the clamp means 31 downward to move the stud 2
By pressing No. 4 into the molten metal on the base metal 26 side, the welding work is completed. 6 shows the stud 2.
4 is a schematic correspondence table showing a schematic correspondence relationship between the diameter D of the reinforcing bar, the welding current value Ia, and the welding time Ta when the reinforcing bar No. 4 is welded by the SAP welding method. Also,
FIG. 7 is a schematic correspondence table showing a schematic correspondence relationship between the diameter φ of the stud dowel, the welding current value Ib, and the welding time Tb when the stud dowel as the stud 24 is welded by the arc stud welding method. . As shown in these schematic correspondence tables, various combinations of the welding current value Ia and the welding time Ta are possible even if the diameter D of the stud 24 is the same. In the above correspondence table, intermediate welding current values Ia and Ib and welding times Ta and Tb are used.
Although the correspondence relationship between and is omitted, the correspondence relationship between them is also stored in detail.

As in the fourth aspect of the invention, the welding current values Ia and Ib measured during welding are input to the CPU 33, and the welding current values Ia and Ib are stored in the storage means 35 and the like. Of the welding current values Ia and Ib stored in correspondence with the diameter D [mm] of
When it is determined that the welding current values Ia and Ib are out of the allowable range, the necessity of readjustment regarding the external characteristics of the welding machine may be indicated via the display means 36. In this case, the CPU 33 and the display means 36 work together to function as an external characteristic monitoring means. Further, when it is determined that the welding current values Ia and Ib actually measured during welding are out of the allowable range as in the invention of claim 5, the CPU 33 externally installed on the welder 21 side. It is also possible to output an operation command to the characteristic adjusting mechanism and automatically perform the readjustment. In this case, the CPU 33 and the external characteristic adjusting mechanism installed on the side of the welding machine 21 work together to function as external characteristic adjusting means.

FIG. 2 is a block diagram showing the essential parts of the second embodiment of the present invention. In the case of the present embodiment, the pushing mechanism 30 in the first embodiment is replaced with a servo mechanism 42 including a servo motor and the stud 2 is used.
Position detecting means 43 including a potentiometer for detecting the height of 4 is provided, and the detection result is input to the CPU 33 to control the servo mechanism 42. Base material 2
It is characterized in that it is configured so as to control the gap with respect to 6 and thus the arc length. In the figure, 44 is the servo mechanism 4.
2 drive circuit, CPU3 via the control cable 45
3 is controlled. In the figure, 46 is an A / D converter and 47 is a D / A converter.

In the case of this embodiment, however, the height of the stud 24 detected by the position detecting means 43 is fed back to the drive control of the servo mechanism 42 as described above, so that the clamp means 31 is moved up and down. Through operation it is possible to precisely control the height of the stud 24. Therefore, as in the third aspect of the invention, the arc voltages Va and Vb during the arc welding are actually measured by the voltage detecting means 37 and input to the CPU 33, and the arc voltages Va and Vb.
b and the optimum arc voltage corresponding to the optimum arc length for the diameter D [mm] of the stud stored in advance in the storage means 35 and the like, and outputs an operation command to the servo mechanism 42 arranged in the welding gun 23. By controlling the height of the stud 24, the arc length can always be controlled to the optimum arc length. That is, in this case, the CPU
33, the voltage detection means 37, the servo mechanism 42, etc. will function as an arc length control means. As described above, in the case of the present embodiment, since the height of the stud 24 is automatically controlled so as to always maintain the optimum arc length, if applied to the deck penetration welding, the deck plate intervenes. In addition, the gap between the stud 24 and the base material 26 is always maintained at a desired gap, which is extremely effective.

Further, as in claim 7, when the downward movement command is output to the servo mechanism 42, the stud 2
It is also possible to instruct to move down at a high speed to a position where 4 touches the molten metal on the base material 26 or in the vicinity thereof, and to move down to a predetermined position in the molten metal at a slow speed thereafter. . In this case, it is possible to prevent the molten metal from scattering due to the pushing of the stud 24, and more quickly push the stud into the molten metal to prevent the deterioration of the welding quality due to the temperature decrease.

[0024]

(1) According to the invention of claim 1, the welding current values Ia and Ib can be kept within a desired range only by performing a short-circuit energization check, and a stable welding state is simple and easy. You can get it accurately. Moreover, since damage to the stud or the like hardly poses a problem in the short-circuit energization check, the desired welding current values Ia and Ib can be obtained without the trouble and cost of replacing the stud. (2) According to the invention of claim 2, the welding current values Ia, Ib.
Even if a normal variation due to the resistance value or the impedance value of the welding current supply circuit is added to the above, it is possible to prevent the welding current values Ia and Ib from being out of the allowable ranges Ja and Jb. (3) According to the invention of claim 3, the diameter D of the stud is
The optimum arc length for [mm] is automatically obtained, and a better welding state can be obtained accurately. (4) According to the invention of claim 4, the welding current values Ia, Ib.
Is further measured, and a check is further added as to whether or not the value is included in the allowable ranges Ja and Jb as the welding current values Ia and Ib to indicate the necessity of readjustment regarding the external characteristics of the welding machine. Therefore, a good welded state can be maintained more reliably. (5) According to the invention of claim 5, it is judged that the measured welding current values Ia, Ib are outside the permissible ranges Ja, Jb as the welding current values Ia, Ib. Since the readjustment regarding the characteristics is automatically performed, the convenience of the welding apparatus is further improved. (6) According to the invention of claim 6, since the welding time is automatically controlled to the optimum welding time for the diameter D [mm] of the stud, a good welding result can be obtained. (7) According to the invention of claim 7, it is possible to prevent the molten metal from scattering due to the pushing of the stud, and more quickly push the stud into the molten metal to prevent the deterioration of the welding quality due to the temperature drop.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main part of a first embodiment of the present invention.

FIG. 2 is a block diagram showing a main part of a second embodiment of the present invention.

FIG. 3 is a relationship diagram showing a correlation between a stud diameter D and a welding current value Ia in the case of the SAP welding method.

FIG. 4 is a relationship diagram showing a correlation between a stud diameter D and a welding current value Ib in the case of the arc stud welding method.

FIG. 5 is an enlarged explanatory view showing a partially enlarged external characteristic of the welding machine.

FIG. 6 is a schematic correspondence table showing a correspondence relationship between the diameter D of the reinforcing bar, the welding current value Ia, and the welding time Ta in the case of the SAP welding method.

FIG. 7 is a schematic correspondence table showing a correspondence relationship between the diameter φ of the stud dowel, the welding current value Ib, and the welding time Tb in the case of the arc stud welding method.

FIG. 8 is a structural conceptual diagram illustrating the entire conventional welding device used for welding studs.

FIG. 9 is an external characteristic diagram illustrating an external characteristic of a welding machine generally used in the SAP welding method.

FIG. 10 is an external characteristic diagram illustrating the external characteristics of a welding machine generally used in the arc stud welding method.

[Explanation of symbols]

21 ... Welding machine, 22 ... Welding cable, 23 ... Welding gun,
24 ... Stud, 25 ... Grounding side cable, 26 ... Base material,
27 ... Control cable, 28 ... Control circuit, 29 ... Control cable, 30 ... Pushing mechanism, 31 ... Clamping means, 3
2 ... Operation part, 33 ... CPU, 34 ... Setting means, 35 ... Storage means, 36 ... Display means, 37 ... Voltage detection means, 38 ...
Current detecting means, 39, 40 ... A / D converter, 41 ... D /
A converter, 42 ... Servo mechanism, 43 ... Position detecting means, 4
4 ... Driving circuit, 45 ... Control cable, 46 ... A / D converter, 47 ... D / A converter, AF ... Characteristic curve, Ga,
Gb ... Lower limit allowable welding current value line, Ha, Hb ... Upper limit allowable welding current value line, Ia, Ib ... Welding current value flowing during welding, Ja, Jb ... Allowable range, Ka, Kb ... Set target current value line, La, Lb ... downward resetting necessity division line, Ma, Mb ... upward resetting necessity division line, Na, N
b ... reset unnecessary area

Claims (7)

[Claims] 1. A storage means for previously obtaining and storing an allowable range for a short-circuit current value Ic in the case where electricity is applied in a state where the stud and the base material are in contact with each other in correspondence with the diameter D of the stud, and the stud and the base material. The short-circuit current value Ic obtained by executing the short-circuit energization check for energizing in the contact state is input, and the short-circuit current value Ic corresponds to the diameter D of the stud stored in the storage means. Ic is included in the allowable range, and when the short-circuit current value Ic is determined to be outside the allowable range by the determining unit, the external characteristics of the welding machine are adjusted and short-circuit energization is performed again. A re-check instruction means for instructing to perform a check, and a welding start suitability when the short-circuit current value Ic obtained by the short-circuit energization check is determined by the determination means to be within the allowable range. A welding device for a stud, comprising a welding start instructing means for instructing that the stud is in a matched state. 2. The allowable range for the short-circuit current value Ic is determined by the SAP welding method according to the welding current values Ia and Ib corresponding to the short-circuit current value Ic included in the allowable range depending on the stud diameter D [mm]. In the case of, Ia = 26D to 30D
[A], Ib = 72D in case of arc stud welding method
The stud welding device according to claim 1, wherein the welding device is set so as to satisfy ~ 84D [A]. 3. The arc voltage during the arc welding is compared with the optimum arc voltage corresponding to the optimum arc length for the diameter D [mm] of the stud, which is stored in advance in the storage means, and the arc voltage is arranged in the welding gun. 2. An arc length control means for outputting an operation command to the servo mechanism is provided.
Alternatively, the welding device for a stud according to item 2. 4. A welding current value I actually measured during welding.
a, Ib are input, and the welding current values Ia, Ib are stored in correspondence with the stud diameter D [mm].
a determining means for determining whether or not the welding current values Ia, Ib actually measured by the determining means are out of the allowable range, and a determination means for determining whether the welding current values Ia, Ib are outside the allowable range. The stud welding device according to any one of claims 1 to 3, further comprising external characteristic monitoring means for indicating the necessity of adjustment. 5. A welding current value I actually measured during welding.
a, Ib are input, and the welding current values Ia, Ib are stored in correspondence with the stud diameter D [mm].
a determining means for determining whether or not the welding current values Ia, Ib measured by the determining means are outside the allowable range, and an external device provided on the welding machine side. The stud welding apparatus according to any one of claims 1 to 3, further comprising an external characteristic adjusting unit that outputs an operation command to the characteristic adjusting mechanism. 6. A welding gun is provided when the elapsed time from the start of welding is measured, and when the elapsed time reaches the optimum welding time for the diameter D [mm] of the stud previously stored in the storage means. The welding time management means for outputting a downward movement command to the servo mechanism which has been performed is provided.
5. The stud welding device according to any one of 5 above. 7. When outputting a down command to the servo mechanism from the welding time management means, the stud is moved down at a high speed to a position at which the stud comes into contact with the molten metal on the base metal or in the vicinity thereof, 7. The welding device for a stud according to claim 6, wherein a command is issued to move down to a predetermined position in the molten metal at a slow speed thereafter.