JP4759233B2 - Non-consumable electrode type gas shielded arc welding power supply - Google Patents

Description

  The present invention relates to a non-consumable electrode-type gas shielded arc welding power source configured to supply a current having an input current value to a welding portion.

  FIG. 5 is a connection diagram of a conventional DC non-consumable electrode type gas shielded arc welding power source.

  In the figure, a main circuit section 1 surrounded by a one-dot chain line includes an input rectifier section 2, a switching section 3, a high-frequency transformer section 4, a secondary rectifier section 5, a current detector 6, a DC reactor 7, and a coupling coil. 8. The positive terminal of the main circuit portion 1 is connected to the welding base material 10, and the negative terminal is connected to the welding torch 9.

  A control unit 11 surrounded by a one-dot chain line includes a switching control unit 12 and an overall control unit 13. Connected to the overall control unit 13 are a set value input unit 15, a torch switch (start switch) 16, an electromagnetic valve 14 for controlling shield gas, and a current detector 6. Note that the set value input unit 15 is provided with a selection switch for selecting self-holding or not self-holding (not shown).

  Next, the operation of a conventional non-consumable electrode type gas shielded arc welding power source will be described.

  When the torch switch 16 is closed, AC supplied from the primary side input power (commercial AC power) is converted to DC by the input rectifier unit 2, then converted to high frequency AC by the switching unit 3, and welded by the high frequency transformer 4. Is converted to a voltage suitable for The high-frequency alternating current output from the high-frequency transformer 4 is converted into direct current again by the secondary rectifier unit 5, and then flows in the order of the direct current reactor 7, the welding base material 10, the welding torch 9, and the coupling coil 8. An arc (not shown) is generated between the welding torch 9.

  The overall control unit 13 compares the current value input to the set value input unit 15 with the current value detected by the current detector 6, amplifies the difference, and inputs the amplified difference to the switching control unit 12. Based on this signal, the switching control unit 12 drives the switching unit 3 so that the current flowing through the welded portion becomes substantially equal to the input current value.

  FIG. 6 is a diagram showing a typical output current waveform of the gas shielded arc welding power source.

When the gas shielded arc welding power source outputs a DC pulse current (hereinafter referred to as “pulse power source”), the current value Ip input to the set value input unit 15 as shown in FIG. , Ib and durations Tp, Tb, the peak current (duration Tp) of the current value Ip and the base current (duration Tb) of the current value Ib are alternately output.

  In the case of pulse welding, the current (average current) having a current value I determined by the following formulas 1 and 2 is simply referred to as current.

I = (Ip · Tp + Ib · Tb) / T0 (Formula 1)
T0 = Tp + Tb (Formula 2)
When the gas shielded arc welding power source outputs a direct current, a current having a current value I input to the set value input unit 15 is output as shown in FIG. Hereinafter, a gas shielded arc welding power source that outputs a current whose current value does not change periodically is referred to as a “DC power source” and is distinguished from a pulse power source. The external connection diagrams of the pulse power supply and the DC power supply are the same, and the pulse power supply has a function of a DC power supply.

  FIGS. 7A and 7B are timing charts during welding in the case of a DC power source. FIG. 7A shows a case where self-holding is not performed, and FIG.

  As will be described later, the usage mode of the open / close signal of the torch switch 16 is different between “with self-holding” and “without self-holding”, and with self-holding, there are a plurality of such as changing the current value during welding. Used when control is required.

In the case of no self-holding, as shown in FIG. 6A, the value of the main current Iw that is a current for performing welding, the value of the preflow time Tg1 in which the shield gas flows before welding, and the oxidation of the welded portion are prevented. Therefore, the value of the postflow time Tg <b> 2 for flowing the shield gas after the end of welding is input to the set value input unit 15.
Next, the operation of the control device 11 when there is no self-holding will be described.

The control device 11 monitors the opening and closing of the torch switch 16, and immediately opens the solenoid valve 14 when the torch switch 16 is closed (on), and during the pulse welding until the torch switch 16 is opened (off) after the preflow time Tg1 has elapsed. The current value of the main current indicating the average current (hereinafter referred to as the main current value) Iw is output to the weld. Then, as soon as the torch switch 16 is opened, the supply of the main current value Iw is stopped, and the solenoid valve 14 is closed after the postflow time Tg2 has elapsed.

  In the case of self-holding, as shown in FIG. 4B, the preflow time Tg1, the postflow time Tg2, the main current value Iw, the current value Is of the start current Is, the current value Ic of the crater current Ic, and the upslope time Tu Each value of the down slope time Td is input to the set value input unit 15.

  Next, the operation of the control device 11 when there is self-holding will be described.

The control device 11 monitors the opening and closing of the torch switch 16, and immediately opens the solenoid valve 14 when the torch switch 16 is closed, and outputs a start current of the current value Is until the torch switch 16 is opened after the preflow time Tg1 has elapsed. . When the torch switch 16 is opened, the current is increased to the main current value Iw during the upslope time Tu, and the main current value Iw is output until the torch switch 16 is opened next. Next, when the torch switch 16 is closed, the current is reduced to the current value Ic during the down slope time Td. Next, when the torch switch 16 is opened, the supply of crater current is stopped, and the electromagnetic valve 14 is closed after the postflow time Tg2 has elapsed.

  In the case of a pulse power supply, it is necessary to input current values Ip and Ib and durations Tp and Tb with respect to the main current value Iw, start current value Is and crater current value Ic, respectively. The same as in the case of a DC power supply.

  Normally, an appropriate main current value Iw is determined according to the object to be welded. However, for unskilled workers, the current value Is, current value Ic, preflow time Tg1, and postflow time Tg2 are parameters that determine welding conditions. Appropriate set values of the up-slope time Tu and the down-slope time Td were not known, and the welding quality was deteriorated. In particular, in the case of a pulse power supply, four values must be set in order to determine one type of current value (for example, the main current value Iw), so that even a skilled worker takes time for setting. .

  Therefore, with one current setting device (in this case, a current setting device for setting the main current value Iw), the current value Ip of the peak current, the current value Ib of the base current, the current value Is of the start current, and the crater current There is a non-consumable electrode-type gas shielded arc welding power source that can set the current value Ic (Patent Document 1).

In Patent Document 1, by providing a current compensator, the current value Ib of the base current does not become smaller than the minimum value Imin of the rated current, and the current value Ip of the peak current is the maximum value Imax of the rated current. I try not to be bigger than that.
Japanese Patent Publication No. 5-56236

  In Patent Document 1, when the main current value Iw in which the current value Ib of the base current is less than the minimum value Imin is selected, the current value Ib of the base current never falls below the minimum value Imin, but the current value of the base current Since Ib becomes larger than the original value, the current value supplied to the welded portion becomes larger than the value set by the current setting device. Therefore, in such a case, trial welding is performed, and the set value of the current setting device is reduced so that the current value supplied to the welded portion becomes a desired current value.

  When the main current value Iw in which the peak current value Ip exceeds the maximum value Imax is selected, the peak current value Ip does not exceed the maximum value Imax, but the peak current value Ip is the original value. Therefore, the current value supplied to the welded portion is smaller than the value set by the current setting device. Therefore, in such a case, trial welding is performed, and the set value of the current setting device is increased so that the current value supplied to the welded portion becomes a desired current value. That is, when the main current value Iw where the current value Ib of the base current is less than the minimum value Imin is selected or when the main current value Iw where the current value Ip of the peak current exceeds the maximum value Imax is selected, Setting was troublesome.

  The object of the present invention is when the main current value Iw where the current value Ib of the base current is less than the minimum value Imin is selected, or when the main current value Iw where the current value Ip of the peak current exceeds the maximum value Imax is selected. It is an object of the present invention to provide a non-consumable electrode type gas shielded arc welding power source that is easy to set current, can be used even by an unskilled worker, and can improve work efficiency.

In order to solve the above-described problem, the present invention provides a non-consumable electrode type gas shielded arc welding power source including a control device that selectively inputs a current having a current value I and supplies the current to a welded portion. The ratio k of the current value Ib of the base current, which is alternately output as the pulse current for each current value Iw of the main current, which is an average current when performing pulse welding, to the current value Ip of the peak current, the current value of the peak current When the pulse welding with the current value Iw of the main current is selected as a welding method, the ratio d of the Ip duration Tp to the pulse period T0 and the frequency fp are set in advance. Based on the current value Iw, the ratio k, the ratio d, the frequency fp, the maximum value Imax of the rated current, and the minimum value Imin of the rated current determined in the table, The pulse period T0, which is the reciprocal of the frequency fp, is calculated by the formula T0 = 1 / fp, and the current value Ip of the peak current constituting the current value Iw of the main current is calculated by the formula Ip = Iw / (d + k · (1-d) ), The current value Ib of the base current that constitutes the current value Iw of the main current is calculated as the duration of the current value Ip of the peak current by the formula Ib = k · Iw / (d + k · (1−d)). Tp is calculated by the formula Tp = d / fp, and the duration Tb for the current value Ib of the base current is calculated by the formula Tb = (1-d) / fp, and the calculated current value Ib and the calculated current The value Ip is compared with the rated current, and when the calculated current value Ib is less than the minimum value Imin of the rated current, the current value Ib is set to the minimum value Imin and the calculation is performed regardless of the value of the ratio k. The The current value Ip is Ip = (Iw− (1−d) · Imin) / d, and when the calculated current value Ip exceeds the maximum value Imax of the rated current, the current value Ip is maximized. The calculated current value Ib is set to Ib = (Iw−d · Imax) / (1−d) regardless of the value of the ratio k, and in other cases, the calculated current value The pulse welding is performed using Ib and the calculated current value Ip.

According to the non-consumable electrode type gas shielded arc welding power source of the present invention, during pulse welding, when the current value of the base current is less than the rated current or when the calculated current value of the peak current exceeds the rated current. mains current values are measures that not a desired current value, with reference to the table set in advance calculation conditions by the controller to the desired current value, as conditions, the current value of the base current is less than rated current If there is a minimum current value of the base current, and to set to a predetermined value of the peak current, the current value of the peak current is the maximum value of the peak current in the case of the maximum value that exceeds the rated current, and a base current to set to a predetermined value, because otherwise controlled to follow the current value calculated, it is easy to set the current, be master in unskilled workers , Thereby improving the working efficiency can be implemented excellent arc welding quality.

  FIG. 1 is a connection diagram of a non-consumable electrode type gas shielded arc welding power source according to the present invention, and those having the same or the same functions as those in FIG.

  The switch 20 is a switch for selecting whether to perform pulse welding using a pulse current or DC welding, and is connected to the overall control unit 13. The overall control unit 13 outputs, via the switching control unit 12, a pulse current when pulse welding is selected, and a direct current when the other (no pulse) is selected.

  The storage device 21 is provided with a condition table 22 describing the values of parameters used for welding, and a storage area 23 for storing the current welding conditions.

  The switch 24 is a switch for use when rewriting the contents of the storage area 23, and is connected to the overall control unit 13.

  Next, the condition table 22 will be described.

  FIG. 2 shows the contents of the condition table according to the present invention.

As shown in the figure, the condition table 22 includes a current ratio k, a time ratio d, a pulse frequency fp, a current ratio s, a current ratio c, and an upslope time, which are parameters for determining welding conditions for each main current value Iw. Tu, downslope time Td, preflow time Tg1, and postflow time Tg2 are set.

Here, the current ratio k is the ratio of the current value Ib of the base current to the current value Ip of the peak current (Ib / Ip), the time ratio d is the ratio of the duration Tp to the pulse period T0, and the current ratio s is the current of the start current . The ratio of the value Is to the main current value Iw and the current ratio c are the ratio of the crater current value Ic to the main current value Iw.

  Next, the operation of the present invention will be described.

FIG. 3 is a flowchart for explaining the welding condition setting procedure according to the present invention, and FIG. 4 is a flowchart for explaining the procedure for determining the peak current value Ip and the base current value Ib in the present invention.

  First, the entire procedure will be described with reference to FIG.

  When the main current value Iw is input and a condition setting button (not shown) is turned on, the control device 11 checks whether pulse welding is performed. If pulse welding is selected, the process of step S20 is performed. In other cases, the process of step S100 is performed (step S10).

  In step S20, it is confirmed whether or not self-holding is performed. If self-holding is performed, the process of step S30 is performed. Otherwise (ie, no self-holding) is performed, the process of step S50 is performed.

In step S30, the main current Iw and primary current values after finding Is the current value of the start current and a coefficient s condition table 22 which is determined by Iw, a current of a current value Ip and the base current of the peak current which constitutes the current value Is The values Ib (hereinafter referred to as “peak current value Ips” and “base current value Ibs” as appropriate ) are obtained by a procedure described later, stored in the storage area 23, and then the process of step S40 is performed.

In step S40, the main current Iw and primary current value after determining the current value Ic of the crater current from the coefficient c of condition table 22 which is determined by Iw, a current of a current value Ip and the base current of the peak current which constitutes the current value Ic The values Ib (hereinafter referred to as “peak current value Ipc” and “base current value Ibc” as appropriate ) are obtained by a procedure described later, stored in the storage area 23, and then the process of step S50 is performed.

In step S50, determined by the procedure described below the current value I b for current Ip and base current of the peak current which constitutes the main current value Iw, performs processing steps S60 from and stored in the storage area 23.

  In step S60, using the time ratio d of the condition table 22 determined by the main current value Iw and the value of the pulse frequency fp, the values of the duration Tp and the duration Tb are calculated by the following equations 4 and 5, and the result is calculated. After storing in the storage area 23, the process of step S70 is performed.

T0 = 1 / fp (Formula 3)
Tp = d · T0 = d / fp (Formula 4)
Tb = (T0−Tp) = (1-d) / fp (Formula 5)
The durations of the current values Ip, Ips, and Ipc of the pulse current are all Tp, and the durations of the current values Ib, Ibs, and Ibc of the base current are all Tb.

  In step S70, the up slope time Tu and the down slope time Td of the condition table 22 determined by the main current value Iw are stored in the storage area 23, and then the process of step S80 is performed.

  In step S80, the preflow time Tg1 and the postflow time Tg2 of the condition table 22 determined by the main current value Iw are stored in the storage area 23, and the process ends.

  In step S100, it is confirmed whether or not self-holding is present. If self-holding is present, the process of step S110 is performed, and otherwise (ie, no self-holding), the process of step S80 is performed.

  In step S110, the current value Is of the start current is calculated from the main current value Iw and the coefficient s in the condition table 22 determined by the main current value Iw, and the result is stored in the storage area 23. Process.

  In step S120, the current value Ic of the crater current is calculated from the main current value Iw and the coefficient c of the condition table 22 determined by the main current value Iw, and the result is stored in the storage area 23. Process.

Next, the procedure for obtaining the current values Ip, Ips, Ipc of the peak current and the current values Ib, Ibs, Ibc of the base current in steps S30 to S50 will be described with reference to FIG.

The current value Ip of the peak current for the current value I is expressed by Equation 6 using the current value I, the current ratio k, and the time ratio d, and the current value Ib of the base current is expressed by Equation 7.

Ip = I / (d + k · (1-d)) (Formula 6)
Ib = k · I / (d + k (1−d)) (Expression 7)
When the current value Is is determined as the current value I, the control device 11 uses Equations 6 and 7 to calculate the current value Ip of the peak current (here, the peak current value Ips) and the current value Ib of the base current (here, the base current value). after determining the ibs) (Step S200), the current value Ip of the peak current to determine whether it is less than the maximum value I max of the rated current, in the case of Ip ≦ Imax performs processing steps S220, otherwise Performs the process of step S250 (step S210).

In step S220, it is confirmed whether or not the current value Ib of the base current is equal to or greater than the minimum value Imin of the rated current. If Ib ≧ Imin, the process of step S270 is performed, and otherwise the process of step S230 is performed.

In step S230, assuming that Ib = Imin, the current value Ip of the peak current is obtained from the following equation 8 (step S240). Then, the current value Ip of the obtained peak current is stored in the storage area 23 as the peak current value Ips, and the value of Ib (in this case, Imin) is stored as the base current value Ibs (step S270).

Further, in step S250, assuming that Ip = Imax, the base current value Ib is obtained by the following equation 9 (step S260), and then the process of step S270 is performed.

Ip = (Iw− (1−d) · Imin) / d (Equation 8)
Ib = (Iw−d · Imax) / (1−d) (Equation 9)
The peak current value Ipc and the base current value Ibc constituting the crater current can be obtained by setting I = Ic in the above-described procedure S40. Also, current values Ib electric current value Ip and the base current of the peak current which constitutes the main current Iw can be obtained by the I = Iw in the procedure S50 in the.

In the upslope time Tu, a base current value Ibs is on the current value Ib of the base current, so that the peak current value Ips shifts to a current value Ip of the peak current to control the current.

In the downslope time Td, the current is controlled such that the current value Ib of the base current shifts to the base current value Ibc and the current value Ip of the peak current shifts to the peak current value Ipc.

  As described above, since all the welding condition parameters for performing the welding are determined, the welding operation is started by closing the torch switch as in the prior art.

As described above, in this embodiment, when the main current value Iw is determined, the preflow time Tg1 and the postflow time Tg2 are set, so that even an unskilled worker can use the work efficiently. Can be improved.

Further, when the main current value Iw is determined, the up slope time Tu and the down slope time Td are set, so that even an unskilled worker can make full use and work efficiency can be improved.

In this embodiment, in the case of pulse welding, the current value Is of the start current and the current value Ic of the crater current are also set to the pulse current. However, even in the case of pulse welding, the current value Is of the start current and the crater current The current value Ic may be a direct current.

  In the above description, the DC current or the peak current and the base current in the pulse current are set to constant values, but the operability and the quality of the welded portion can be improved by changing each value.

  If the parameter value stored in the storage area 23 is to be changed due to, for example, the shape of the welded part being special, it is stored in the storage area 23 by the switch 24 prior to the start of welding. The stored contents can be changed.

  In the above description, the main current is determined before the start of welding. However, it can be changed even during welding.

  In this embodiment, the current ratio k and the time ratio d are changed according to the main current value Iw, but may be fixed values.

  Further, in this embodiment, the welding condition parameter is always determined based on the main current value Iw. However, a selection switch for selecting whether or not to apply the present invention is provided so that the application of the present invention can be selected. Good.

It is a connection diagram of a non-consumable electrode type gas shielded arc welding power source according to the present invention. It is a figure which shows the content of the condition table which concerns on this invention. It is a flowchart explaining the welding condition setting procedure which concerns on this invention. It is a flowchart explaining the determination procedure of the peak current value Ip and the base current value Ib in the present invention. It is a connection diagram of a conventional direct current non-consumable electrode type gas shielded arc welding power source. It is a figure which shows the typical output current waveform of a gas shielded arc welding power supply. It is a timing chart at the time of welding in the case of DC power supply.

Explanation of symbols

22 condition table Iw main current Ip pulse current current value Ib based current current value of the

Claims (1)

In a non-consumable electrode type gas shielded arc welding power source equipped with a control device for selectively inputting a current of current value I and supplying the current to a welded portion,
The control device is configured such that the ratio k of the current value Ib of the base current, which is alternately output as the pulse current for each current value Iw of the main current, which is an average current when performing pulse welding, to the current value Ip of the peak current, the peak A table in which a ratio d of a current value Ip of a current to a pulse period T0 of a duration Tp and a frequency fp are set in advance;
When the pulse welding based on the current value Iw of the main current is selected as a welding method, the current value Iw of the main current, the ratio k, the ratio d, the frequency fp, and the rated current defined in the table The pulse period T0, which is the reciprocal of the frequency fp, based on the maximum value Imax and the minimum value Imin of the rated current is a peak current constituting the current value Iw of the main current according to the formula T0 = 1 / fp. The current value Ip of the base current constituting the current value Iw of the main current is calculated by the formula Ip = Iw / (d + k · (1−d)). -D)), the duration Tp for the current value Ip of the peak current is calculated by the formula Tp = d / fp, and the duration Tb for the current value Ib of the base current is calculated by the formula Tb = (1-d / Fp and the calculated current value Ib and the calculated current value Ip are compared with the rated current. If the calculated current value Ib is less than the minimum value Imin of the rated current, the current value Ib is set to the minimum value Imin, the calculated current value Ip is set to Ip = (Iw− (1−d) · Imin) / d regardless of the value of the ratio k, and the calculated current value Ip Exceeds the maximum value Imax of the rated current, the current value Ip is set to the maximum value Imax, and the calculated current value Ib is set to Ib = (Iw−d · Imax) regardless of the value of the ratio k. / (1-d), and in other cases, the pulse current welding is performed using the calculated current value Ib and the calculated current value Ip. Power supply.

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