JP2002346758A - Projection welding method, and projection welding equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect and display any explosion occurring by inputting excessive heat in a weld part when welding is carried out utilizing the resistance heat generation. SOLUTION: A projection welding equipment comprises a mean resistance calculator 10 for calculating the mean resistance in a predetermined period after completing the conduction set by a time setting unit 9 by inputting the output signal of a resistance calculator 7 and the output signal of the time setting unit 9, a reference resistance setting unit 11 for setting the reference resistance, a comparator 12 which inputs the output signal of the mean resistance calculator 10 and the output signal of the reference resistance setting unit 11 to compare levels of both output signals, and outputs the explosion occurrence signal when the output resistance of the mean resistance calculator 10 exceeds the reference resistance of the reference resistance setting unit 11, and an explosion display 13 which receives the output signal of the comparator 12 and displays occurrence of the explosion only when the explosion occurrence signal is present. When explosion is detected, it can be displayed, and a weld work 50 in which explosion occurs therein can be removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a projection welding method and a projection welding apparatus.

[0002]

2. Description of the Related Art Projection welding is a method of joining works by utilizing resistance heat generated when a current is intensively applied to a projection portion brought into close contact with a constant pressing force. A schematic diagram is shown in FIG. In order to obtain stable joining quality, it is needless to say that the design of the projection part is important, but it is necessary to stabilize the resistance heat generation at the work contact part. As a control technique for stabilizing the resistance heat generation of the contact portion, for example, the amount of electric power supplied to the welding work 50 is made constant, or the temperature of the joint is detected and the welding current and the conduction time are controlled accordingly. Has been proposed and put to practical use.

[0003]

However, in actual welding work, there is a dimensional error in the projection part manufactured by press working, a work installation error caused by an error between the welded work and the jig, and an adhesion to the projection part in the manufacturing process. Oil and green matter that have deteriorated the welding quality as disturbance factors. For example, due to the influence of these factors, an excessively large or small amount of heat may be supplied to the welding work. If the heat input to the welding work is too small, the joint cannot be formed well. Conversely, if the input heat amount is too large, there is a possibility that a part of the joint of the welded work is melted and a part of the melted metal is scattered. Usually, scattering of a part of the molten metal is also referred to as explosion.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a projection welding method capable of detecting a blast generated by applying an excessive amount of heat to a joint when welding using resistance heating and displaying the same. It is to provide a projection welding device.

[0005]

According to a first aspect of the present invention, there is provided a projection welding method utilizing resistance heat generated when a current is intensively applied to a joint of a welding work. In the projection welding method for joining, when the average resistance for a certain period from the end of energization exceeds a reference value, it is determined that a blast has occurred, and it is indicated that a blast has occurred.

As described above, when the average resistance for a certain period from the end of energization exceeds the reference value, it is determined that a blast has occurred. Therefore, the average resistance value for a certain period from the end of energization is constant. When the explosion is equal to or more than the reference value, the explosion is considered to have occurred, and the fact that the explosion has occurred is displayed, whereby the welding work having the explosion can be removed.

A projection welding method according to a second aspect of the present invention is a projection welding method in which resistance heat generated when a current is intensively applied to a joint portion of a welded work is used for joining for a predetermined period from the end of energization. When the maximum resistance exceeds a reference value, it is determined that a blast has occurred, and the fact that a blast has occurred is displayed.

In this way, when the maximum resistance for a certain period from the end of energization exceeds the reference value, it is determined that a blast has occurred. When the explosion is equal to or more than the reference value, the explosion is considered to have occurred, and the fact that the explosion has occurred is displayed, whereby the welding work having the explosion can be removed.

According to a third aspect of the present invention, there is provided a projection welding method for joining by utilizing resistance heat generated when a current is intensively applied to a joint portion of a welding work, wherein the welding is performed for a certain period from the end of energization. When the differential value of the resistance value exceeds the reference value, it is determined that a blast has occurred,
Indicates that a blast has occurred.

As described above, when the differential value of the resistance value for a certain period from the end of energization exceeds the reference value, it is determined that a blast has occurred. When the differential value exceeds a certain reference value,
By regarding that a blast has occurred and displaying that a blast has occurred, it is possible to remove the welded work having the blast.

According to a fourth aspect of the present invention, there is provided a projection welding method for performing joining by utilizing resistance heat generated when current is intensively applied to a joint portion of a welding work, wherein an average resistance during an energization period is reduced. When the reference value is exceeded, it is determined that a blast has occurred, and the fact that a blast has occurred is displayed.

Thus, when the average resistance during the power-on period exceeds the reference value, it is determined that a blast has occurred. Therefore, when the average resistance value during the power-on period exceeds a certain reference value, By regarding that a blast has occurred and displaying that a blast has occurred, it is possible to remove the welded work having the blast.

According to a fifth aspect of the present invention, there is provided a projection welding method for joining by utilizing resistance heat generated when a current is intensively applied to a joint portion of a welding work. When the reference value is exceeded, it is determined that a blast has occurred, and the fact that a blast has occurred is displayed.

Thus, when the maximum resistance during the power-on period exceeds the reference value, it is determined that a blast has occurred. Therefore, when the maximum resistance value during the power-on period exceeds a certain reference value, By regarding that a blast has occurred and displaying that a blast has occurred, it is possible to remove the welded work having the blast.

According to a sixth aspect of the present invention, there is provided a projection welding method for performing joining by utilizing resistance heat generated when current is intensively applied to a joint portion of a welding work. When the differential value exceeds the reference value, it is determined that a blast has occurred, and the fact that a blast has occurred is displayed.

As described above, when the differential value of the resistance value during the power-on period exceeds the reference value, it is determined that a blast has occurred. Therefore, the differential value of the resistance value during the power-on period is equal to or greater than a certain reference value. , The explosion is considered to have occurred, and by displaying that the explosion has occurred, the welding work having the explosion can be removed.

According to a seventh aspect of the present invention, there is provided a projection welding method for performing joining by utilizing resistance heat generated when current is intensively applied to a joint portion of a welded work, wherein the welding is performed for a predetermined period from the end of energization. When the average voltage exceeds a reference value, it is determined that a blast has occurred, and it is displayed that a blast has occurred.

As described above, when the average voltage for a certain period from the end of energization exceeds the reference value, it is determined that a blast has occurred. Therefore, the average voltage value for a certain period from the end of energization is constant. When the explosion is equal to or more than the reference value, the explosion is considered to have occurred, and by displaying that the explosion has occurred, the welding work having the explosion can be removed.

According to a eighth aspect of the present invention, there is provided a projection welding method for performing joining by utilizing resistance heat generated when a current is intensively applied to a joint portion of a welding work, wherein the welding is performed for a predetermined period from the end of energization. When the maximum voltage exceeds a reference value, it is determined that a blast has occurred, and the fact that a blast has occurred is displayed.

As described above, when the maximum voltage for a certain period from the end of energization exceeds the reference value, it is determined that a blast has occurred. Therefore, the maximum voltage value for a certain period from the end of energization is constant. When the explosion is equal to or more than the reference value, the explosion is considered to have occurred, and the fact that the explosion has occurred is displayed, whereby the welding work having the explosion can be removed.

According to a ninth aspect of the present invention, there is provided a projection welding method for joining by utilizing resistance heat generated when a current is intensively applied to a joint portion of a welding work, wherein the welding is performed for a predetermined period from the end of energization. When the differential value of the voltage value exceeds the reference value, it is determined that a blast has occurred,
Indicates that a blast has occurred.

As described above, when the differential value of the voltage value for a certain period from the end of energization exceeds the reference value, it is determined that a blast has occurred. When the differential value exceeds a certain reference value,
By regarding that a blast has occurred and displaying that a blast has occurred, it is possible to remove the welded work having the blast.

According to a tenth aspect of the present invention, there is provided a projection welding method for joining by utilizing resistance heat generated when a current is intensively applied to a joint portion of a welding work. When the reference value is exceeded, it is determined that a blast has occurred, and the fact that a blast has occurred is displayed.

As described above, when the average voltage during the energization period exceeds the reference value, it is determined that a blast has occurred. Therefore, when the average voltage value during the energization period exceeds a certain reference value, By regarding that a blast has occurred and displaying that a blast has occurred, it is possible to remove the welded work having the blast.

[0025] The projection welding method according to the eleventh aspect is a projection welding method in which resistance heat generated when a current is intensively applied to a joint portion of a welded work is used for joining, wherein a maximum voltage during a power-on period is reduced. When the reference value is exceeded, it is determined that a blast has occurred, and the fact that a blast has occurred is displayed.

As described above, when the maximum voltage during the power-on period exceeds the reference value, it is determined that a blast has occurred. Therefore, when the maximum voltage value during the power-on period exceeds a certain reference value, By regarding that a blast has occurred and displaying that a blast has occurred, it is possible to remove the welded work having the blast.

According to a twelfth aspect of the present invention, there is provided a projection welding method for joining by utilizing resistance heat generated when a current is intensively applied to a joint of a welding work. When the differential value exceeds the reference value, it is determined that a blast has occurred, and the fact that a blast has occurred is displayed.

As described above, when the differential value of the voltage value during the energization period exceeds the reference value, it is determined that a blast has occurred. , The explosion is considered to have occurred, and by displaying that the explosion has occurred, the welding work having the explosion can be removed.

According to a thirteenth aspect of the present invention, there is provided a projection welding method for performing joining by utilizing resistance heat generated when a current is intensively applied to a joint portion of a welding work, wherein the welding is performed for a certain period from the end of energization. When the average resistance exceeds the reference value, it is determined that a blast has occurred, the fact that a blast has occurred is displayed, and the welding output is reduced.

As described above, when the average resistance for a certain period from the end of energization exceeds the reference value, it is determined that a blast has occurred, and the welding output is reduced. When the resistance value exceeds a certain reference value, it is considered that a blast has occurred, and by displaying that a blast has occurred, the welded work with the blast can be removed and the next time By lowering the welding output by welding, it is possible to prevent explosion from occurring.

According to a fourteenth aspect of the present invention, there is provided a projection welding apparatus, comprising: a current detector and a voltage detector for detecting a current and a voltage at a joint of a welding work; A resistance calculator for calculating a resistance value, a sequence setting device for setting a sequence of welding energization, a time setting device for inputting a setting signal of the sequence setting device, and setting a time from the end of energization; An output signal of the calculator and an output signal of the time setting device are input, and an average resistance calculator for calculating an average resistance for a certain period after the end of energization set by the time setting device, and a reference resistance value are set. A reference resistance setter, an output signal of the average resistance calculator and an output signal of the reference resistance setter are input, and a magnitude relationship between the two is compared, and an output resistance of the average resistance calculator is output. A comparator that outputs a blast generation signal when the value exceeds the reference resistance value of the reference resistance setting device, and receives an output signal of the comparator, only when there is a blast generation signal, a blast occurs. And a blast indicator for displaying the fact.

As described above, the output signal of the average resistance calculator and the output signal of the reference resistance setter for a certain period from the end of the energization of the welding are input, and the magnitude relation between them is compared. And a comparator that outputs a blast generation signal when the output resistance value of the reference exceeds the reference resistance value of the reference resistance setting device, and a blast occurs only when there is a blast generation signal when the output signal of the comparator is received. The explosion indicator displays that the explosion has occurred, so when the output resistance value of the average resistance calculator exceeds a preset reference resistance value, the comparator generates a blast occurrence signal and displays the blast The device can remove the explosive welding work by receiving the explosion generating signal from the comparator and displaying that the explosion has occurred.

According to a fifteenth aspect of the present invention, the projection welding apparatus receives a current detector and a voltage detector for detecting a current and a voltage at a joint portion of the welding work, and inputs detection signals of the current detector and the voltage detector. A resistance calculator for calculating a resistance value, a sequence setting device for setting a sequence of welding energization, a time setting device for inputting a setting signal of the sequence setting device, and setting a time from the end of energization; Inputting the output signal of the calculator and the output signal of the time setting device, and setting a maximum resistance calculator for calculating the maximum resistance for a certain period after the end of energization set by the time setting device, and a reference resistance value. A reference resistance setter, an output signal of the maximum resistance calculator and an output signal of the reference resistance setter are input, and the magnitude relation between the two is compared. A comparator that outputs a blast generation signal when the value exceeds the reference resistance value of the reference resistance setting device, and receives an output signal of the comparator, only when there is a blast generation signal, a blast occurs. And a blast indicator for displaying the fact.

As described above, the output signal of the maximum resistance calculator and the output signal of the reference resistance setter are input during a certain period from the end of the energization of the welding, and the magnitude relation between them is compared. And a comparator that outputs a blast generation signal when the output resistance value of the reference exceeds the reference resistance value of the reference resistance setting device, and a blast occurs only when there is a blast generation signal when the output signal of the comparator is received. And the explosion indicator that indicates that the explosion has occurred.When the output resistance value of the maximum resistance calculator exceeds a preset reference resistance value, the comparator generates a blast occurrence signal and displays the blast The device can remove the explosive welding work by receiving the explosion generating signal from the comparator and displaying that the explosion has occurred.

According to a sixteenth aspect of the present invention, there is provided a projection welding apparatus comprising: a current detector and a voltage detector for detecting a current and a voltage at a joint of a welding work; and a detection signal of the current detector and the voltage detector. A resistance calculator for calculating a resistance value, a sequence setting device for setting a sequence of welding energization, a time setting device for inputting a setting signal of the sequence setting device, and setting a time from the end of energization; A resistance differential calculator that receives the output signal of the calculator and the output signal of the time setting device and calculates the differential value of the resistance value for a certain period after the end of energization set by the time setting device; A reference resistance differentiation setter for setting a value, an output signal of the resistance differentiation calculator and an output signal of the reference resistance differentiation setter are input, and a magnitude relationship between the two is compared. A comparator that outputs a blast generation signal when the output resistance differential value of the minute calculator exceeds the reference resistance differential value of the reference resistance differential setter, and a blast generation signal that receives the output signal of the comparator. And a blast indicator that indicates that a blast has occurred.

As described above, the output signal of the resistance differential calculator and the output signal of the reference resistance differential setter for a certain period from the end of the welding energization are input, and the magnitude relation between the two is compared. A comparator that outputs a blast generation signal when the output resistance differential value of the detector exceeds the reference resistance differential value of the reference resistance differential setting device, and only when there is a blast generation signal A blast indicator is provided to indicate that a blast has occurred.When the output resistance differential value of the resistance differential calculator exceeds a preset reference resistance differential value, the comparator outputs a blast generation signal. Then, the explosion indicator receives the explosion occurrence signal from the comparator and indicates that an explosion has occurred, so that the welding work having the explosion can be removed.

According to a seventeenth aspect of the present invention, the projection welding apparatus receives a current detector and a voltage detector for detecting a current and a voltage at a joint portion of the welding work, and inputs detection signals of the current detector and the voltage detector. A resistance calculator for calculating a resistance value, a sequence setting device for setting a sequence of welding energization, an output signal of the resistance calculator and an output signal of the sequence setting device are input, and an average resistance during the energization period is calculated. An average resistance calculator to be calculated, a reference resistance setter to set a reference resistance value, and an output signal of the average resistance calculator and an output signal of the reference resistance setter are input, and a comparison of the magnitude relationship between the two is performed. A comparator that outputs a blast generating signal when an output resistance value of the average resistance calculator exceeds a reference resistance value of the reference resistance setting device, and receives an output signal of the comparator to generate a blast Only when No. there is, and a 爆飛 display for displaying that the 爆飛 occurred.

As described above, the output signal of the average resistance calculator for calculating the average resistance during the energization period and the output signal of the reference resistance setting device are input, and the magnitude relation between them is compared. And a comparator that outputs a blast generation signal when the output resistance value of the reference exceeds the reference resistance value of the reference resistance setting device, and a blast occurs only when there is a blast generation signal when the output signal of the comparator is received. With a blast indicator that indicates
When the output resistance value of the average resistance calculator exceeds a preset reference resistance value, the comparator generates a blast generation signal, and the blast indicator receives the blast generation signal from the comparator and blasts. By displaying that the welding has occurred, the welding work having the explosion can be removed.

In the projection welding apparatus according to the present invention, a current detector and a voltage detector for detecting a current and a voltage at a joint of a welding work, and detection signals of the current detector and the voltage detector are inputted, A resistance calculator for calculating a resistance value, a sequence setting device for setting a sequence of welding energization, an output signal of the resistance calculator and an output signal of the sequence setting device are input, and the maximum resistance during the energization period is set. A maximum resistance calculator to be calculated, a reference resistance setter to set a reference resistance value, and an output signal of the maximum resistance calculator and an output signal of the reference resistance setter are input, and a comparison of the magnitude relationship between the two is performed. A comparator that outputs a blast generation signal when an output resistance value of the maximum resistance calculator exceeds a reference resistance value of the reference resistance setting device, and receives an output signal of the comparator to generate a blast Only when No. there is, and a 爆飛 display for displaying that the 爆飛 occurred.

As described above, the output signal of the maximum resistance calculator for calculating the maximum resistance during the energization period and the output signal of the reference resistance setting device are input, and the magnitude relation between them is compared. And a comparator that outputs a blast generation signal when the output resistance value of the reference exceeds the reference resistance value of the reference resistance setting device, and a blast occurs only when there is a blast generation signal when the output signal of the comparator is received. With a blast indicator that indicates
When the output resistance value of the maximum resistance calculator exceeds a preset reference resistance value, the comparator generates a blast generation signal, and the blast indicator receives the blast generation signal from the comparator and blasts. By displaying that the welding has occurred, the welding work having the explosion can be removed.

According to a nineteenth aspect of the present invention, the projection welding apparatus receives a current detector and a voltage detector for detecting a current and a voltage at a joint of a welding work, and inputs detection signals of the current detector and the voltage detector. A resistance calculator for calculating a resistance value, a sequence setting device for setting a sequence of welding energization, an output signal of the resistance calculator and an output signal of the sequence setting device are input, and the resistance value during the energization period is input. A differential resistance calculating device for calculating a differential value, a standard differential setting device for setting a differential reference value, an output signal of the differential resistance calculating device and an output signal of the standard differential setting device are input. , Compare the size of the two,
A comparator that outputs a blast occurrence signal when an output resistance differential value of the resistance differential resistance calculator exceeds a reference resistance differential value of the reference resistance differential setter, and receives an output signal of the comparator;
A blast indicator is provided to indicate that a blast has occurred only when there is a blast occurrence signal.

As described above, the output signal of the resistance differential resistance calculator for calculating the differential value of the resistance value during the energization period and the output signal of the reference resistance differential setter are input, and the magnitude relation between the two is compared. , A comparator that outputs a blast generation signal when the output resistance differential value of the resistance differential resistance calculator exceeds the reference resistance differential value of the reference resistance differential setter, and receives the output signal of the comparator, and the blast generation signal A bomb blast indicator that indicates that a blast has occurred is provided only when there is a difference.When the output resistance derivative of the resistance derivative calculator exceeds a preset reference resistance resistance derivative, the comparator Generates a blast occurrence signal, and the blast indicator displays the occurrence of the blast by receiving the blast generation signal from the comparator, thereby eliminating the blast welding work. .

According to a twentieth aspect of the projection welding apparatus, a voltage detector for detecting a voltage at a joint portion of a welding work, a sequence setting device for setting a welding energizing sequence, and a setting signal of the sequence setting device are input. A time setting device for setting the time from the end of energization,
An average voltage calculator that receives an output signal of the voltage detector and an output signal of the time setting device, calculates an average voltage for a certain period after the end of energization set by the time setting device, and a reference voltage value. The reference voltage setter to be set, the output signal of the average voltage calculator and the output signal of the reference voltage setter are input, and the magnitude relation between the two is compared, and the output voltage value of the average voltage calculator is A comparator that outputs a blast generation signal when the reference voltage value of the reference voltage setter is exceeded, and that the blast occurs only when there is a blast generation signal in response to the output signal of the comparator. And a blast indicator for displaying.

As described above, the output signal of the average voltage calculator and the output signal of the reference voltage setter during a certain period from the end of the welding energization are input, and the magnitude relation between the two is compared. A comparator that outputs a blast generating signal when the output voltage value of the calculator exceeds the reference voltage value of the reference voltage setting device, and only when there is a blast generating signal, receiving the output signal of the comparator, A blast indicator is provided to indicate that a blast has occurred.When the output voltage value of the average voltage calculator exceeds a preset reference voltage value, the comparator generates a blast signal. The blast indicator can remove the blasted welding work by receiving a blast generation signal from the comparator and displaying that a blast has occurred.

According to a twenty-first aspect of the invention, a projection welding apparatus receives a voltage detector for detecting a voltage at a joint portion of a welding work, a sequence setting device for setting a welding energizing sequence, and a setting signal of the sequence setting device. A time setting device for setting the time from the end of energization,
A maximum voltage calculator that receives an output signal of the voltage detector and an output signal of the time setting device, calculates a maximum voltage for a certain period after the end of energization set by the time setting device, and a reference voltage value. The reference voltage setter to be set, the output signal of the maximum voltage calculator and the output signal of the reference voltage setter are input, and the magnitude relation between the two is compared, and the output voltage value of the maximum voltage calculator is A comparator that outputs a blast generation signal when the reference voltage value of the reference voltage setter is exceeded, and that the blast occurs only when there is a blast generation signal in response to the output signal of the comparator. And a blast indicator for displaying.

As described above, the output signal of the maximum voltage calculator and the output signal of the reference voltage setter are input during a certain period from the end of welding energization, and the magnitude relation between them is compared. A comparator that outputs a blast generation signal when the output voltage value of the reference exceeds the reference voltage value of the reference voltage setting device, and a blast occurs only when there is a blast generation signal when the output signal of the comparator is received. And the explosion indicator that indicates that the explosion has occurred.When the output voltage value of the maximum voltage calculator exceeds a preset reference voltage value, the comparator generates an explosion signal and displays the explosion. The device can remove the explosive welding work by receiving the explosion generating signal from the comparator and displaying that the explosion has occurred.

According to a twenty-second aspect of the invention, a projection welding apparatus receives a voltage detector for detecting a voltage at a joint portion of a welding work, a sequence setting device for setting a welding energizing sequence, and a setting signal of the sequence setting device. A time setting device for setting the time from the end of energization,
A voltage derivative calculator that receives an output signal of the voltage detector and an output signal of the time setting device, and calculates a differential value of a voltage value for a certain period after the end of energization set by the time setting device; A reference voltage differentiation setting device for setting a voltage differentiation value;
The output signal of the voltage derivative calculator and the output signal of the reference voltage derivative setter are input, and the magnitude relationship between the two is compared. The output voltage derivative of the voltage derivative calculator is the reference voltage derivative setter. A comparator that outputs a blast occurrence signal when the reference voltage differential value is exceeded, and receives an output signal of the comparator,
A blast indicator is provided to indicate that a blast has occurred only when there is a blast occurrence signal.

As described above, the output signal of the voltage derivative calculator and the output signal of the reference voltage derivative setter for a certain period from the end of the energization of the welding are input, and the magnitude relation between the two is compared. A comparator that outputs a blast generation signal when the output voltage differential value of the device exceeds the reference voltage differential value of the reference voltage differentiation setting device, and only when there is a blast generation signal A blast indicator is provided to indicate that a blast has occurred.When the output voltage derivative of the voltage derivative calculator exceeds a preset reference voltage derivative, the comparator generates a blast signal. Then, the explosion indicator receives the explosion occurrence signal from the comparator and indicates that an explosion has occurred, so that the welding work having the explosion can be removed.

A projection welding apparatus according to claim 23, wherein a voltage detector for detecting a voltage at a joint portion of a welding work, a sequence setting device for setting a welding energizing sequence, an output signal of the voltage detector and the sequence. An output signal of the setting device is input, an average voltage calculator for calculating an average voltage during the energization period, a reference voltage setting device for setting a reference voltage value, an output signal of the average voltage calculator and the reference voltage By inputting the output signal of the setter and comparing the magnitude relation between the two, a bomb blast generation signal is output when the output voltage value of the average voltage calculator exceeds the reference voltage value of the reference voltage setter. A comparator, receiving an output signal of the comparator;
A blast indicator is provided to indicate that a blast has occurred only when there is a blast occurrence signal.

As described above, the output signal of the average voltage calculator for calculating the average voltage during the energization period and the output signal of the reference voltage setting device are input, and the magnitude relation between them is compared. A comparator that outputs a blast generation signal when the output voltage value of the reference exceeds the reference voltage value of the reference voltage setting device, and a blast occurs only when there is a blast generation signal when the output signal of the comparator is received. With a blast indicator that indicates
When the output voltage value of the average voltage calculator exceeds a preset reference voltage value, the comparator generates a blast generation signal, and the blast indicator receives the blast generation signal from the comparator and blasts. By displaying that the welding has occurred, the welding work having the explosion can be removed.

According to a twenty-fourth aspect of the present invention, in the projection welding apparatus, a voltage detector for detecting a voltage at a joint portion of the welding work, a sequence setting device for setting a welding energizing sequence, an output signal of the voltage detector and the sequence. Inputting the output signal of the setting device, a maximum voltage calculator for calculating the maximum voltage during the energization period, a reference voltage setting device for setting a reference voltage value, an output signal of the maximum voltage calculator and the reference voltage By inputting the output signal of the setting device and comparing the magnitude relationship between the two, a bomb blast generation signal is output when the output voltage value of the maximum voltage calculator exceeds the reference voltage value of the reference voltage setting device. A comparator, receiving an output signal of the comparator;
A blast indicator is provided to indicate that a blast has occurred only when there is a blast occurrence signal.

As described above, the output signal of the maximum voltage calculator for calculating the maximum voltage during the energization period and the output signal of the reference voltage setting device are input, and the magnitude relation between them is compared. A comparator that outputs a blast generation signal when the output voltage value of the reference exceeds the reference voltage value of the reference voltage setting device, and a blast occurs only when there is a blast generation signal when the output signal of the comparator is received. With a blast indicator that indicates
When the output voltage value of the maximum voltage calculator exceeds a preset reference voltage value, the comparator generates a blast generation signal, and the blast indicator receives the blast generation signal from the comparator and blasts. By displaying that the welding has occurred, the welding work having the explosion can be removed.

A projection welding apparatus according to a twenty-fifth aspect of the present invention provides a projection welding apparatus, comprising: a voltage detector for detecting a voltage at a joint portion of a welding work; a sequence setting device for setting a welding energizing sequence; An output signal of the setting device is input, a voltage differentiation calculator for calculating a differential value of a voltage value during the energization period, a reference voltage differentiation setting device for setting a reference voltage differentiation value, and an output of the voltage differentiation calculator. A signal and an output signal of the reference voltage setting device are input, and the magnitude relation between them is compared, and the output voltage differentiation value of the voltage differentiation calculator exceeds the reference voltage differentiation value of the reference voltage differentiation setting device. A comparator that sometimes outputs a blast occurrence signal,
A blast indicator that receives the output signal of the comparator and displays that a blast has occurred only when there is a blast generation signal.

As described above, the output signal of the voltage derivative calculator for calculating the differential value of the voltage value during the energization period and the output signal of the reference voltage setting device are input, and the magnitude relation between them is compared. A comparator that outputs a blast generation signal when the output voltage differential value of the derivative calculator exceeds the reference voltage differential value of the reference voltage differential setting device, and when a blast generation signal is received upon receiving the comparator output signal However, since it has a blast indicator that indicates that a blast has occurred, when the output voltage derivative of the voltage derivative calculator exceeds a preset reference voltage derivative,
The comparator generates an explosion signal, and the explosion indicator receives the explosion signal from the comparator and indicates that an explosion has occurred, thereby removing the explosive welding work. Can be.

According to a twenty-sixth aspect of the present invention, there is provided a projection welding apparatus, comprising: a current detector and a voltage detector for detecting a current and a voltage at a joint of a welding work; and a detection signal of the current detector and the voltage detector. A resistance calculator for calculating a resistance value, a sequence setting device for setting a sequence of welding energization, a time setting device for inputting a setting signal of the sequence setting device, and setting a time from the end of energization; An output signal of the calculator and an output signal of the time setting device are input, and an average resistance calculator for calculating an average resistance for a certain period after the end of energization set by the time setting device, and a reference resistance value are set. A reference resistance setter, an output signal of the average resistance calculator and an output signal of the reference resistance setter are input, and a magnitude relationship between the two is compared, and an output resistance of the average resistance calculator is output. A comparator that outputs a blast generation signal when the value exceeds the reference resistance value of the reference resistance setting device, and receives an output signal of the comparator, only when there is a blast generation signal, a blast occurs. A blast indicator that indicates that there is no blast at the start of welding, receives the output signal of the comparator, and determines whether or not there is a blast according to the presence or absence of a blast generation signal. A blast generation memory for storing and outputting the signal, receiving the output of the blast generation storage, and reducing the welding output to the joint of the welding work only when receiving a blasting presence signal. And a controller for controlling.

As described above, the output signal of the average resistance calculator and the output signal of the reference resistance setter during a certain period from the end of the welding energization are input, and the magnitude relation between them is compared. And a comparator that outputs a blast generation signal when the output resistance value of the reference exceeds the reference resistance value of the reference resistance setting device, and a blast occurs only when there is a blast generation signal when the output signal of the comparator is received. A blast indicator that indicates that blasting has occurred and, at the start of welding, memorizes that there is no blasting, receives the output signal of the comparator, and determines whether or not there is a blasting according to the presence or absence of a blasting occurrence signal. A blast generation memory that stores and outputs the signal,
The controller has a controller that controls the output of the explosion generation memory to reduce the welding output to the joint of the welding work only when the explosion signal is received. When the value exceeds a preset reference resistance value, the comparator generates a blast generation signal, and the blast indicator indicates that a blast has occurred in response to the blast generation signal from the comparator. This makes it possible to remove the explosive welding work. At the start of the first welding, the blast generation memory stores no blast, but thereafter, depending on the presence or absence of the blast generation signal from the comparator, the presence of a blast is determined. Is stored, and the signal is output to the controller.The controller reduces the explosion by lowering the welding output to the joint of the welding work only when receiving the explosion signal from the explosion generation memory. Flying can be prevented from occurring.

[0057]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing a projection welding apparatus according to a first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a rectifier that receives a three-phase input and converts the DC to DC, 2 denotes a control element that converts the DC of the rectifier 1 to AC, and 3 denotes an AC converted by the control element 2 for welding. Transformers 4 for converting to a required voltage are rectifiers for converting the output of the transformer 3 to DC.
Reference numerals 5 and 6 denote a current detector and a voltage detector for detecting a current and a voltage at the joint portion of the welding work 50, and 7 calculates a resistance value by inputting output signals of the current detector 5 and the voltage detector 6. 8 is a sequence setting device for setting a welding sequence; 9 is a time setting device for receiving an output signal of the sequence setting device and setting a fixed time from the end of energization; Is an average resistance calculator that receives the output signals of the heater 7 and the time setting device 9 and calculates an average resistance value for a certain period from the end of energization. 11 is a reference resistance setter for setting a reference resistance value, 1
Reference numeral 2 denotes a comparator which receives an output signal of the reference resistance of the reference resistance setting device 11 and an output signal of the average resistance calculated from the average resistance calculator 10 and compares the two signals with each other.
Reference numeral 3 denotes a blast indicator that indicates that a blast has occurred only when there is an input signal from the comparator 12, and 14 receives the sequence signal set by the sequence setting device 8, and 2 to the welding work 50
Is a controller for controlling the welding of the joints.

The operation of this embodiment will be described.
The resistance calculator 7 receives the detection current of the current detector 5 and the detection voltage of the voltage detector 6 as inputs, calculates a resistance value at each time point, and outputs the resistance value to the average resistance calculator 10. Time setting device 9
Inputs the energization sequence signal set by the sequence setting unit 8, sets a certain time from the end of energization, and outputs the same to the average resistance calculator 10. The average resistance calculator 10
In response to the output signal of the resistance calculator 7 and the output signal of the time setting unit 9, an average resistance value for a certain period from the end of energization is calculated and output to the comparator 12. The comparator 12 compares the average resistance value with the reference resistance value set by the reference resistance setting device 11, and determines that a blast has occurred when the average resistance value exceeds the reference resistance value. The flying occurrence signal is output to the explosion indicator 13. The blast indicator 13 indicates that a blast has occurred only when there is an input signal from the comparator 12.

Here, the projection welding method of this embodiment will be described. FIG. 2 is a schematic diagram showing an example of a resistance value waveform of the projection welding.

Resistance waveform when no explosion occurs (curve 1)
Will be described. Since the contact of the contact portion at the beginning of the energization is incomplete, the contact area is small and the resistance value is large. Thereafter, the contact portion is plastically deformed together with heat generation, so that the contact area increases and the resistance value decreases. When the energization becomes longer, heat is mainly generated by the volume resistance of the projection part, and the resistance value increases again with the rise in temperature. The resistance value until the end of welding is determined by the change in the current path due to the heat generated at the contact portion and the plastic deformation. In a very short period immediately after the end of the energization, the secondary circuit that supplies electricity to the weld has an inductance. Therefore, even if the energization signal is off, a current flows until the energy stored in the inductance is consumed. By detecting the current and voltage during this period, the resistance value can be calculated. When there is no explosion, since the temperature of the joint immediately after the end of the energization is still high, the calculated resistance value is almost the same level as that immediately before the end of the energization.

Next, a description will be given of a resistance value waveform when an explosion occurs. Curve 2a is a waveform when the degree of explosion is small and a part of the molten metal scatters. At this time, the current path is secured by the remaining metal, but the resistance value increases due to the decrease in the current area. During a certain period after the end of the energization, the resistance value calculated from the current and the voltage increases due to a surge effect due to the inductance existing in the secondary circuit of welding. FIG. 3 shows an example of actually measured values of the resistance value waveform of the projection welding.

On the other hand, the curve 2b is a waveform when the degree of explosion is large and the energization is cut off during energization. In the welding at this time, the current path is lost due to the splatter of the molten metal at the joint. Thus, the effect of the surge voltage due to the inductance present in the secondary circuit of the welding is greater. As described above, the explosion can be detected and displayed using the phenomenon of the increase in the resistance value for a certain period after the end of energization caused by the explosion.

More specifically, when joining is performed by using resistance heat generated when a current is intensively applied to the joining portion, when the average resistance for a certain period from the end of energization of welding exceeds a reference value. Judge that a blast has occurred and display it. It is possible to automatically or manually remove the exploded welding work.

In the projection welding method and the projection welding apparatus configured as described above, when a blast is detected, it can be displayed immediately, and the blast welded workpiece can be removed.

In the above embodiment, the three-phase AC is converted to DC by the rectifier 1 and then converted again to AC by the control element 2 and input to the transformer 3. An element for controlling the alternating current may be used. In this case, the rectifier 1 is unnecessary. Further, although the output of the transformer 3 is changed to DC by the rectifier 4 and then supplied to the welding work 50, the output may be directly supplied to the welding work 50. Although not shown, the voltage detection line input to the voltage detector 6 should be
It is desirable to attach to the tip of the electrode close to the welding work 50. In addition, the explosion indicator 13 is an LED, a lamp, a liquid crystal,
Any of an alarm and the like may be used.

A second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram showing a projection welding apparatus according to a second embodiment of the present invention.

A maximum resistance calculator 15 is used instead of the average resistance calculator 10 in the embodiment shown in FIG.
The description of the same configuration and operation as in the embodiment of the invention shown in FIG. 1 will be omitted. The maximum resistance calculator 15 calculates the maximum resistance value for a certain period from the end of welding, set by the time setting device 9, and outputs the calculated maximum resistance value to the comparator 12.

In the projection welding method and the projection welding apparatus, when the maximum resistance value for a certain period from the end of energization exceeds a preset reference value, it is determined that a blast has occurred. According to this embodiment configured as described above, the above-described effects can be obtained.

A third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram showing a projection welding apparatus according to a third embodiment of the present invention.

In the embodiment shown in FIG. 1, instead of the average resistance calculator 10, a resistance differential calculator 16 is used, and instead of the reference resistance setter 11, a reference resistance differential setter that sets a reference value of a resistance differential value. 17 is used. The description of the same configuration and operation as in the embodiment of the invention shown in FIG. 1 will be omitted. The resistance differential calculator 16 inputs the voltage value calculated by the resistance calculator 7 to obtain the differential value, and outputs to the comparator 12 only the differential value for a certain period from the end of welding set by the time setting device 9. I do. In the comparator 12, the resistance differential calculator 1
6 is compared with the reference value of the reference resistance differential setter 17, and when the calculated value exceeds the reference value, it is determined that a blast has occurred, and a blast generation signal is displayed on the blast indicator 13. Output.

Here, the reason for using the differential resistance value will be described. As shown in FIG. 2, the resistance value when a blast explodes greatly increases. However, when an explosion occurs and the amount of scattered molten metal is very small, the amount of increase in resistance is also small. At this time, the explosion detection can be more reliably realized by using the differential resistance value.

In the projection welding method and the projection welding apparatus, when the differential value of the resistance value for a certain period from the end of energization exceeds a predetermined reference value, it is determined that a blast has occurred. According to this embodiment configured as described above, the above-described effects can be obtained.

A fourth embodiment of the present invention will be described with reference to FIG. FIG. 6 is a block diagram showing a projection welding apparatus according to a fourth embodiment of the present invention.

An average resistance calculator 18 is used instead of the average resistance calculator 10 in the embodiment shown in FIG. 1, and the signal of the time setting device 9 inputted to the average resistance calculator 10 becomes unnecessary. The setting signal of the sequence setting device 8 is directly input to the average resistance calculator 18. The description of the same configuration and operation as in the embodiment of the invention shown in FIG. 1 will be omitted. The average resistance calculator 18 receives the output signals of the sequence setting unit 8 and the resistance calculator 7, calculates the average resistance during the energization period, and outputs the average resistance to the comparator 12.

In the projection welding method and the projection welding apparatus, when the average resistance value during the power-on period exceeds a predetermined reference value, it is determined that a blast has occurred. According to this embodiment configured as described above, the above-described effects can be obtained.

A fifth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a block diagram showing a projection welding apparatus according to a fifth embodiment of the present invention.

A maximum resistance calculator 19 is used instead of the average resistance calculator 10 in the embodiment shown in FIG. 1, and the signal of the time setting device 9 inputted to the average resistance calculator 10 becomes unnecessary. The setting signal of the sequence setting device 8 is directly input to the maximum resistance calculator 19. The description of the same configuration and operation as in the embodiment of the invention shown in FIG. 1 will be omitted. The maximum resistance calculator 19 receives the output signals of the sequence setting unit 8 and the resistance calculator 7, calculates the maximum resistance during the energization period, and outputs the calculated maximum resistance to the comparator 12.

In the projection welding method and the projection welding apparatus, when the maximum resistance value during the energization period exceeds a predetermined reference value, it is determined that a blast has occurred. According to this embodiment configured as described above, the above-described effects can be obtained.

A sixth embodiment of the present invention will be described with reference to FIG. FIG. 8 is a block diagram showing a projection welding apparatus according to a sixth embodiment of the present invention.

In the embodiment shown in FIG. 1, instead of the average resistance calculator 10, a resistance differential calculator 20 is used, and instead of the reference resistance setter 11, a reference resistance differential setter that sets a reference value of a resistance differential value. 17, the signal of the time setting device 9 inputted to the average resistance calculator 10 becomes unnecessary,
The setting signal of the sequence setting device 8 is directly input to the resistance differential calculator 20. The description of the same configuration and operation as in the embodiment of the invention shown in FIG. 1 will be omitted. The resistance derivative calculator 20 receives the resistance value calculated by the resistance calculator 7, obtains its differential value, and outputs all the differential values during the energization period to the comparator 12. The comparator 12 compares the calculated value of the resistance differential calculator 20 with the reference value of the reference resistance differential setter 17, and when the calculated value exceeds the reference value, determines that a blast has occurred, The generated signal is output to the blast indicator 13.

In the projection welding method and the projection welding apparatus, when the differential value of the resistance value during the energization period exceeds a predetermined reference value, it is determined that the explosion has occurred. According to this embodiment configured as described above, the above-described effects can be obtained.

FIGS. 9 to 1 show a seventh embodiment of the present invention.
1 based on the appearance. FIG. 9 is a block diagram showing a projection welding apparatus according to a seventh embodiment of the present invention.

In FIG. 9, reference numeral 1 denotes a rectifier for receiving a three-phase input and converting it to DC, 2 a control element for converting the DC of the rectifier 1 to AC, and 3 a welding element for converting the AC converted by the control element 2 to welding. Transformers 4 for converting to a required voltage are rectifiers for converting the output of the transformer 3 to DC. 6
Is a voltage detector for converting the voltage at the joint of the welding work 50, 8 is a sequence setting device for setting a welding sequence, 9 is an output signal of the sequence setting device,
Time setting device for setting a fixed time from the end of energization, 2
1 is an average voltage calculator for inputting output signals of the voltage detector 6 and the time setting device 9 and calculating an average voltage for a certain period from the end of energization, and 22 is a reference voltage for setting a reference voltage value. A setter 12 receives a reference voltage of the reference voltage setter 22 and an average voltage from the average voltage calculator 21 and compares the magnitudes of the two. Only when there is an input signal, a blast indicator 14 that indicates that a blast has occurred, receives a sequence signal set by the sequence setting unit 8 and sends a control signal to the control element 2 to send a welding work. This is a controller for controlling the welding of the 50 joints.

The operation of this embodiment will be described.
The time setting device 9 receives the energization sequence signal set by the sequence setting device 8, sets a certain time from the end of energization, and outputs the same to the average voltage calculator 21. The average voltage calculator 21 receives the output signal of the voltage detector 6 and the output signal of the time setting device 9, calculates an average voltage value for a certain period from the end of energization, and outputs the average voltage value to the comparator 12. Comparator 1
2 compares the average voltage value with a reference voltage set by the reference voltage setting device 22, determines that a blast has occurred when the average voltage exceeds the reference voltage value, and outputs a blast generation signal. Output to the blast indicator 13. The blast indicator 13 indicates that a blast has occurred only when there is an input signal from the comparator 12.

Here, the tendency of the voltage change during welding in the projection welding method of this embodiment will be described. FIG. 10 is a characteristic diagram showing an example of the voltage waveform of the projection welding.

The voltage waveform (curve 1) when no explosion occurs, that is, during normal welding will be described. The voltage value at the beginning of energization is an initial voltage value before the molten silicon work is heated. As the welding work is heated, the voltage increases from the initial voltage. Its initial voltage rise rate is high. As the welding progresses, the joint portion of the welding work is plastically deformed, so that the energizing path is widened and the energizing path may be shortened by the plastic deformation. Therefore, in a normal case, the rate of voltage rise in the latter half of welding decreases. After the energization, the current flows for a while due to the influence of the inductance in the secondary circuit from the welding transformer to the welding work, so that the voltage decreases until the current becomes 0V.

Next, the voltage waveform at the time of the explosion will be described. Curve 2a is a waveform when the degree of explosion is small and a part of the molten metal at the joint scatters. The tendency of the voltage change during the energization period shows the same tendency as when there is no explosion. However, although the energization path is secured by the remaining metal due to the explosion, the resistance value increases due to the decrease in the energization area. Therefore, during a certain period after the end of energization, the voltage rises in the form of a surge voltage due to the influence of the inductance in the secondary circuit of welding.
The curve 2b is a waveform when the degree of explosion is large and the power supply is cut off during power supply. In this waveform, the current path is lost due to the splatter of the molten metal at the joint. FIG. 11 shows an example (corresponding to the curve 2a in FIG. 10) of an actually measured value of the voltage waveform of the projection welding. As described above, the explosion is detected using the phenomenon of voltage increase that occurs due to the explosion for a certain period after the end of energization,
It can be displayed.

Specifically, when joining is performed by using resistance heat generated when current is intensively applied to the joint, when the average voltage for a certain period from the end of the energization of welding exceeds a reference value. Judge that a blast has occurred and display it. It is possible to automatically or manually remove the exploded welding work.

In the projection welding method and the projection welding apparatus configured as described above, when a blast is detected, it can be displayed immediately, and the welded workpiece with the blast can be removed.

In the above embodiment, the three-phase AC is converted to DC by the rectifier 1 and then converted again to AC by the control element 2 and input to the transformer 3. A controlling element may be used. In this case, the rectifier 1 is unnecessary. Further, although the output of the transformer 3 is changed to DC by the rectifier 4 and then supplied to the welding work 50, the output may be directly supplied to the welding work 50. Although not shown, the voltage detection line input to the voltage detector 6 should be
It is desirable to attach to the tip of the electrode close to the welding work 50.

An eighth embodiment of the present invention will be described with reference to FIG. FIG. 12 is a block diagram showing a projection welding apparatus according to an eighth embodiment of the present invention.

A maximum voltage calculator 23 is used instead of the average voltage calculator 21 in the embodiment shown in FIG.
The description of the same configuration and operation as in the embodiment of the invention shown in FIG. 9 will be omitted. The maximum voltage calculator 23 calculates the maximum voltage value for a certain period from the end of welding, set by the time setting device 9, and outputs it to the comparator 12.

In the projection welding method and the projection welding apparatus, when the maximum voltage value in a certain period from the end of energization exceeds a preset reference value, it is determined that a blast has occurred. According to this embodiment configured as described above, the above-described effects can be obtained.

A ninth embodiment of the present invention will be described with reference to FIG. FIG. 13 is a block diagram showing a projection welding apparatus according to a ninth embodiment of the present invention.

A voltage differential calculator 24 is used instead of the average voltage calculator 21 in the embodiment shown in FIG. 9, and a reference voltage differentiator for setting a reference value of the voltage differential value is used instead of the reference voltage setter 22. The setting device 25 is used. Note that FIG.
The description of the same configuration and operation as in the embodiment of the invention shown in FIG. The voltage derivative calculator 24 receives the detected voltage value of the voltage detector 6 and obtains a differential value of the voltage value.
And outputs only the differential value for a certain period from the end of welding set in the comparator 12 to the comparator 12. The comparator 12 compares the value calculated by the voltage derivative calculator 24 with the reference value of the reference voltage derivative setter 25. When the calculated value exceeds the reference value, it is determined that a blast has occurred. The generated signal is output to the blast indicator 13.

In the projection welding method and the projection welding apparatus, when the differential value of the voltage value for a certain period from the end of energization exceeds a preset reference value, it is determined that a blast has occurred. According to this embodiment configured as described above, the above-described effects can be obtained.

A tenth embodiment of the present invention will be described with reference to FIG. FIG. 14 is a block diagram showing a projection welding apparatus according to a tenth embodiment of the present invention.

An average voltage calculator 26 is used instead of the average voltage calculator 21 in the embodiment shown in FIG. 9, and the signal of the time setting device 9 inputted to the average voltage calculator 21 becomes unnecessary. The setting signal of the sequence setting device 8 is directly input to the average voltage calculator 26. The description of the same configuration and operation as in the embodiment of the invention shown in FIG. 9 will be omitted. The average voltage calculator 26 receives the output signals of the sequence setter 8 and the voltage detector 6, calculates an average voltage during the energization period, and outputs the average voltage to the comparator 12.

In the projection welding method and the projection welding apparatus, when the average voltage value during the energization period exceeds a preset reference value, it is determined that a blast has occurred. According to this embodiment configured as described above, the above-described effects can be obtained.

An eleventh embodiment of the present invention will be described with reference to FIG. FIG. 15 is a block diagram showing a projection welding apparatus according to an eleventh embodiment of the present invention.

A maximum voltage calculator 27 is used instead of the average voltage calculator 21 in the embodiment shown in FIG. 9, and the signal of the time setting device 9 inputted to the average voltage calculator 21 becomes unnecessary. The setting signal of the sequence setting device 8 is directly input to the maximum voltage calculator 27. The description of the same configuration and operation as in the embodiment of the invention shown in FIG. 9 will be omitted. The maximum voltage calculator 27 receives the output signals of the sequence setting device 8 and the voltage detector 6, calculates the maximum voltage during the energization period, and outputs the maximum voltage to the comparator 12.

In the projection welding method and the projection welding apparatus, when the maximum voltage value during the energization period exceeds a preset reference value, it is determined that a blast has occurred. According to this embodiment configured as described above, the above-described effects can be obtained.

The twelfth embodiment of the present invention will be described with reference to FIG. FIG. 16 is a block diagram showing a projection welding apparatus according to a twelfth embodiment of the present invention.

[0105] Instead of the average voltage calculator 21 in the embodiment shown in FIG. 9, a voltage derivative calculator 28 is used instead of the reference voltage setter 22, and a reference voltage derivative setter that sets a reference value of the voltage derivative. 25, the signal of the time setting device 9 input to the average voltage calculator 21 becomes unnecessary,
The setting signal of the sequence setting device 8 is directly input to the voltage differentiation calculator 28. The description of the same configuration and operation as in the embodiment of the invention shown in FIG. 9 will be omitted. The voltage derivative calculator 28 receives the detected voltage value of the voltage detector 6, obtains its derivative value, and outputs all of the derivative values during the energization period to the comparator 12. The comparator 12 compares the calculated value of the voltage derivative calculator 28 with the reference value of the reference voltage derivative setter 25. When the calculated value exceeds the reference value, it is determined that a blast has occurred. The generated signal is output to the blast indicator 13.

According to the projection welding method and the projection welding apparatus, when the differential value of the voltage value during the energization period exceeds a preset reference value, it is determined that a blast has occurred. According to this embodiment configured as described above, the above-described effects can be obtained.

A thirteenth embodiment of the present invention will be described with reference to FIG. FIG. 17 is a block diagram showing a projection welding apparatus according to an embodiment of the present invention.

In FIG. 17, reference numeral 1 denotes a rectifier that receives a three-phase input and converts it to DC, 2 denotes a control element that converts the DC of the rectifier 1 to AC, and 3 denotes an AC converted by the control element 2 for welding. Transformers 4 for converting to a required voltage are rectifiers for converting the output of the transformer 3 to DC.
Reference numerals 5 and 6 denote a current detector and a voltage detector for detecting a current and a voltage at the joint portion of the welding work 50, and 7 calculates a resistance value by inputting output signals of the current detector 5 and the voltage detector 6. 8 is a sequence setting device for setting a welding sequence; 9 is a time setting device for receiving an output signal of the sequence setting device and setting a fixed time from the end of energization; Is an average resistance calculator that receives the output signals of the heater 7 and the time setting device 9 and calculates an average resistance value for a certain period from the end of energization. 11 is a reference resistance setter for setting a reference resistance value, 1
Reference numeral 2 denotes a comparator which receives an output signal of the reference resistance of the reference resistance setting device 11 and an output signal of the average resistance calculated from the average resistance calculator 10 and compares the two signals with each other.
Reference numeral 3 denotes a blast indicator that indicates that a blast has occurred only when there is an input signal from the comparator 12, and 29 indicates a state of whether or not there is a blast when the output signal of the comparator 12 is received. Receiving the output signal of the explosion generation storage 29 and the sequence signal set by the sequence setting device 8, sends a control signal to the control element 2, and outputs a welding work 50. Is a controller for controlling the welding of the joints.

The operation of this embodiment will be described.
The resistance calculator 7 receives the detection current of the current detector 5 and the detection voltage of the voltage detector 6 as inputs, calculates a resistance value at each time point, and outputs the calculated resistance value to the average resistance calculator 10. Time setting device 9
Inputs the energization sequence signal set by the sequence setting unit 8, sets a certain time from the end of energization, and outputs the same to the average resistance calculator 10. The average resistance calculator 10
In response to the output signal of the resistance calculator 7 and the output signal of the time setting unit 9, an average resistance value for a certain period from the end of energization is calculated and output to the comparator 12. The comparator 12 compares the average resistance value with the reference resistance value set by the reference resistance setting device 11, and determines that a blast has occurred when the average resistance value exceeds the reference resistance value. The flight generation signal is output to the blast display 13 and the blast generation storage 29. The blast indicator 13 indicates that a blast has occurred only when there is an input signal from the comparator 12. The blast generation memory 29
At the start of the first welding, it is stored that there is no explosion. After that, depending on the presence or absence of the explosion generation signal from the comparator 12, the presence or absence of the explosion is stored, and the signal is stored. Output to the controller 29. The controller 30 controls the control element 2 so as to supply the same welding output as the previous welding to the welding work 50 when the controller 30 receives the signal indicating that there is no explosion from the explosion generation storage 29. The control element 2 is controlled so that a welding output of a lower level than the previous welding is supplied to the welding work 50 only when a bomb blasting signal from the generation memory 29 is received.

In the projection welding method and the projection welding apparatus configured as described above, when a blast is detected, it can be displayed immediately, and the blast welding work can be removed. Since the welding output can be changed according to the result of whether or not the explosion occurred in the previous welding, the occurrence of the explosion can be prevented.

In the above embodiment, the three-phase AC is converted to DC by the rectifier 1 and then converted again to AC by the control element 2 and input to the transformer 3. A controlling element may be used. In this case, the rectifier 1 is unnecessary. Further, the output of the transformer 3 is supplied to the welding work 50 after being changed to DC by the rectifier 4, but the output may be supplied directly to the welding work 50. Although not shown, the voltage detection line input to the voltage detector 6 should be
It is desirable to attach to the tip of the electrode close to the welding work 50. In addition, the explosion indicator 13 is an LED, a lamp, a liquid crystal,
Any of an alarm and the like may be used. In addition, explosion generation memory 2
9 can use storage means such as a memory, a register, and a RAM.

[0112]

According to the projection welding method of the first aspect of the present invention, it is determined that a blast has occurred when the average resistance for a certain period from the end of energization exceeds a reference value. When the average resistance value for a certain period from the end point exceeds a certain reference value, it is considered that a blast has occurred, and by displaying that a blast has occurred, the welding work with the blast has been detected. Can be removed.

According to the projection welding method of the present invention, when the maximum resistance for a certain period from the end of energization exceeds the reference value, it is determined that a blast has occurred. When the maximum resistance value for a certain period of time exceeds a certain reference value, it is considered that a blast has occurred, and by displaying that a blast has occurred, the welded work with the blast is removed. be able to.

According to the projection welding method of the third aspect of the present invention, when the differential value of the resistance value for a certain period from the end of energization exceeds the reference value, it is determined that a blast has occurred. When the differential value of the resistance value for a certain period from the end of energization exceeds a certain reference value, it is considered that a blast has occurred, and by displaying that a blast has occurred, there was a blast. The welding work can be removed.

According to the projection welding method of the fourth aspect of the present invention, when the average resistance during the power-on period exceeds the reference value, it is determined that a blast has occurred. When it exceeds a certain standard value,
By regarding that a blast has occurred and displaying that a blast has occurred, it is possible to remove the welded work having the blast.

According to the projection welding method of the fifth aspect of the present invention, when the maximum resistance during the energizing period exceeds the reference value, it is determined that a blast has occurred. When it exceeds a certain standard value,
By regarding that a blast has occurred and displaying that a blast has occurred, it is possible to remove the welded work having the blast.

According to the projection welding method of the sixth aspect of the present invention, when the differential value of the resistance value during the energization period exceeds the reference value, it is determined that a blast has occurred. When the differential value of the value exceeds a certain reference value, it is considered that a blast has occurred, and by displaying that the blast has occurred, the welded work having the blast can be removed.

According to the projection welding method of the present invention, when the average voltage for a certain period from the end of energization exceeds the reference value, it is determined that a blast has occurred. When the average voltage value for a certain period of time exceeds a certain reference value, it is considered that a blast has occurred, and by displaying that a blast has occurred, the welding work with the blast is removed. be able to.

According to the projection welding method of the present invention, when the maximum voltage for a certain period from the end of energization exceeds the reference value, it is determined that a blast has occurred. When the maximum voltage value for a certain period of time exceeds a certain reference value, it is considered that a blast has occurred, and by displaying that a blast has occurred, the welded work with the blast is removed. be able to.

According to the projection welding method of the ninth aspect of the present invention, when the differential value of the voltage value for a certain period from the end of energization exceeds the reference value, it is determined that a blast has occurred. When the differential value of the voltage value for a certain period from the end of the energization exceeds a certain reference value, it is considered that a blast has occurred, and by displaying that a blast has occurred, there was a blast. The welding work can be removed.

According to the projection welding method of the tenth aspect of the present invention, when the average voltage during the energizing period exceeds the reference value, it is determined that a blast has occurred. When the value exceeds a certain reference value, it is considered that a blast has occurred, and by displaying that the blast has occurred, the welded work having the blast can be removed.

According to the projection welding method of the present invention, when the maximum voltage during the power-on period exceeds the reference value, it is determined that a blast has occurred. When the value exceeds a certain reference value, it is considered that a blast has occurred, and by displaying that a blast has occurred, the welding work having the blast can be removed.

According to the projection welding method of the twelfth aspect of the present invention, when the differential value of the voltage value during the energization period exceeds the reference value, it is determined that a blast has occurred.
When the differential value of the voltage value during the energization period exceeds a certain reference value, it is considered that a blast has occurred, and by displaying that a blast has occurred, the welded workpiece with the blast is removed. can do.

According to the projection welding method of the thirteenth aspect of the present invention, when the average resistance for a certain period from the end of energization exceeds a reference value, it is determined that a blast has occurred and the welding output is reduced. When the average resistance value for a certain period from the end of the energization of welding became equal to or more than a certain reference value, it was considered that a blast occurred and displayed that a blast occurred. Since the welding work can be removed and the welding output can be changed according to the result of whether the explosion occurred in the previous welding, by lowering the welding output in the next welding,
Explosion can be prevented from occurring.

According to the projection welding apparatus of the fourteenth aspect of the present invention, the output signal of the average resistance calculator and the output signal of the reference resistance setter for a certain period from the end of the welding energization are input, and both of them are input. Comparing the magnitude relationship, a comparator that outputs a blast generation signal when the output resistance value of the average resistance calculator exceeds the reference resistance value of the reference resistance setting device, and a blast occurs when the output signal of the comparator is received A blast indicator is provided to indicate that a blast has occurred only when there is a signal, so when the output resistance of the average resistance calculator exceeds a preset reference resistance, the comparator A blast generating signal is generated, and the blast indicator displays the occurrence of the blast in response to the blast generating signal from the comparator, whereby the welding work having the blast can be removed.

According to the projection welding apparatus of the fifteenth aspect of the present invention, the output signal of the maximum resistance calculator and the output signal of the reference resistance setter for a certain period from the end of the welding energization are input, and both of them are input. Comparing the magnitude relationship, a comparator that outputs a blast generation signal when the output resistance value of the maximum resistance calculator exceeds the reference resistance value of the reference resistance setter, and a blast occurs when the output signal of the comparator is received A blast indicator that indicates that a blast has occurred is provided only when a signal is present, so when the output resistance of the maximum resistance calculator exceeds a preset reference resistance, the comparator A blast generating signal is generated, and the blast indicator displays the occurrence of the blast in response to the blast generating signal from the comparator, whereby the welding work having the blast can be removed.

According to the projection welding apparatus of the sixteenth aspect of the present invention, the output signal of the resistance differential calculator and the output signal of the reference resistance differential setter for a certain period from the end of the energization of the welding are input, and both are input. And a comparator that outputs a blast occurrence signal when the output resistance differential value of the resistance differential calculator exceeds the reference resistance differential value of the reference resistance differential setter, and receives the output signal of the comparator. A blast indicator is provided to indicate that a blast has occurred only when there is a blast occurrence signal, so that the output resistance differential value of the resistance differential calculator exceeds the preset reference resistance differential value. The explosion signal is generated by the comparator, and the explosion indicator displays the occurrence of the explosion by receiving the explosion signal from the comparator. Can be removed.

According to the projection welding apparatus of the present invention, the output signal of the average resistance calculator for calculating the average resistance during the energization period and the output signal of the reference resistance setter are input, and Comparing the magnitude relationship, a comparator that outputs a blast generation signal when the output resistance value of the average resistance calculator exceeds the reference resistance value of the reference resistance setting device, and a blast occurs when the output signal of the comparator is received A blast indicator is provided to indicate that a blast has occurred only when there is a signal, so when the output resistance of the average resistance calculator exceeds a preset reference resistance, the comparator Generates a blast occurrence signal,
The explosion indicator displays the occurrence of the explosion in response to the explosion signal from the comparator, so that the welding work having the explosion can be removed.

According to the projection welding apparatus of the eighteenth aspect of the present invention, the output signal of the maximum resistance calculator for calculating the maximum resistance during the energization period and the output signal of the reference resistance setter are inputted, and Comparing the magnitude relationship, a comparator that outputs a blast generation signal when the output resistance value of the maximum resistance calculator exceeds the reference resistance value of the reference resistance setter, and a blast occurs when the output signal of the comparator is received A blast indicator that indicates that a blast has occurred is provided only when a signal is present, so when the output resistance of the maximum resistance calculator exceeds a preset reference resistance, the comparator Generates a blast occurrence signal,
The explosion indicator displays the occurrence of the explosion in response to the explosion signal from the comparator, so that the welding work having the explosion can be removed.

According to the projection welding apparatus of the nineteenth aspect of the present invention, the output signal of the resistance differential resistance calculator for calculating the differential value of the resistance value during the energization period and the output signal of the reference resistance differential setter are input. Then, a comparison is made between the magnitudes of the two, and a comparator that outputs a blast generation signal when the output resistance differential value of the resistance differential resistance calculator exceeds the reference resistance differential value of the reference resistance differential setter, and a comparator And a blast indicator that indicates that a blast has occurred only when there is a blast generation signal. When the resistance value exceeds the resistance differential value, the comparator generates a blast signal, and the blast indicator displays the occurrence of the blast by receiving the blast signal from the comparator. To remove welded work Kill.

According to the projection welding apparatus of the twentieth aspect of the present invention, the output signal of the average voltage calculator and the output signal of the reference voltage setter are input during a certain period from the end of the welding energization. And a comparator that outputs a blast generation signal when an output voltage value of the average voltage calculator exceeds a reference voltage value of the reference voltage setting device, and receives an output signal of the comparator. A blast indicator is provided to indicate that a blast has occurred only when there is a blast occurrence signal, so when the output voltage value of the average voltage calculator exceeds a preset reference voltage value , The comparator generates a blast signal, and the blast indicator removes the blast welding work by receiving the blast signal from the comparator and displaying that a blast has occurred. be able to.

According to the projection welding apparatus of the twenty-first aspect of the present invention, the output signal of the maximum voltage calculator and the output signal of the reference voltage setter are input during a certain period from the end of welding power supply, and both of them are input. Comparing the magnitude relationship, a comparator that outputs a blast generation signal when the output voltage value of the maximum voltage calculator exceeds the reference voltage value of the reference voltage setting device, and a blast occurs when the output signal of the comparator is received A blast indicator that indicates that a blast has occurred is provided only when there is a signal, so when the output voltage value of the maximum voltage calculator exceeds a preset reference voltage value, the comparator A blast generating signal is generated, and the blast indicator displays the occurrence of the blast in response to the blast generating signal from the comparator, whereby the welding work having the blast can be removed.

According to the projection welding apparatus of the twenty-second aspect of the present invention, the output signal of the voltage derivative calculator and the output signal of the reference voltage derivative setter are input during a certain period from the end of welding power supply. And a comparator that outputs a blast generation signal when the output voltage derivative of the voltage derivative calculator exceeds the reference voltage derivative of the reference voltage derivative setter, and receives the output signal of the comparator. And a blast indicator that indicates that a blast has occurred only when there is a blast occurrence signal, so that the output voltage derivative of the voltage derivative calculator exceeds the preset reference voltage derivative. The explosion signal is generated by the comparator, and the explosion indicator displays the occurrence of the explosion by receiving the explosion signal from the comparator. Can be removed.

According to the projection welding apparatus of the twenty-third aspect of the present invention, the output signal of the average voltage calculator for calculating the average voltage during the energization period and the output signal of the reference voltage setting device are input, and Comparing magnitude relations, a comparator that outputs a blast generation signal when the output voltage value of the average voltage calculator exceeds the reference voltage value of the reference voltage setting device, and a blast occurs when the output signal of the comparator is received A blast indicator is provided to indicate that a blast has occurred only when there is a signal.When the output voltage of the average voltage calculator exceeds a preset reference voltage, the comparator Generates a blast occurrence signal,
The explosion indicator displays the occurrence of the explosion in response to the explosion signal from the comparator, so that the welding work having the explosion can be removed.

According to the projection welding apparatus of the twenty-fourth aspect of the present invention, the output signal of the maximum voltage calculator for calculating the maximum voltage during the energization period and the output signal of the reference voltage setting device are inputted, and both of them are inputted. Comparing the magnitude relationship, a comparator that outputs a blast generation signal when the output voltage value of the maximum voltage calculator exceeds the reference voltage value of the reference voltage setting device, and a blast occurs when the output signal of the comparator is received A blast indicator that indicates that a blast has occurred is provided only when there is a signal, so when the output voltage value of the maximum voltage calculator exceeds a preset reference voltage value, the comparator Generates a blast occurrence signal,
The explosion indicator displays the occurrence of the explosion in response to the explosion signal from the comparator, so that the welding work having the explosion can be removed.

According to the projection welding apparatus of the twenty-fifth aspect of the present invention, the output signal of the voltage differential calculator for calculating the differential value of the voltage value during the energization period and the output signal of the reference voltage setting device are inputted. , Compare the size of the two,
There is a comparator that outputs a blast generation signal when the output voltage differential value of the voltage derivative calculator exceeds the reference voltage differential value of the reference voltage differentiation setting device, and there is a blast generation signal when the output signal of the comparator is received. Only when the explosion has occurred, a blast indicator is provided to indicate that a blast has occurred.When the output voltage derivative of the voltage derivative calculator exceeds a preset reference voltage derivative, the comparator An explosion signal is generated, and the explosion indicator receives the explosion generation signal from the comparator and indicates that an explosion has occurred, thereby removing the explosive welding work.

According to the projection welding apparatus of the twenty-sixth aspect of the present invention, the output signal of the average resistance calculator and the output signal of the reference resistance setter for a certain period from the end of the welding energization are input, and both of them are input. Comparing the magnitude relationship, a comparator that outputs a blast generation signal when the output resistance value of the average resistance calculator exceeds the reference resistance value of the reference resistance setting device, and a blast occurs when the output signal of the comparator is received A blast indicator that indicates that a blast has occurred only when there is a signal, and memorizes that there is no blast at the start of welding, receives a comparator output signal, and responds to the presence or absence of a blast signal. And a blast generation memory that stores the presence and absence of a blast and outputs the signal.
The controller has a controller that controls the output of the explosion generation memory to reduce the welding output to the joint of the welding work only when the explosion signal is received. When the value exceeds a preset reference resistance value, the comparator generates a blast generation signal, and the blast indicator indicates that a blast has occurred in response to the blast generation signal from the comparator. This makes it possible to remove the explosive welding work. At the start of the first welding, the blast generation memory stores no blast, but thereafter, depending on the presence or absence of the blast generation signal from the comparator, the presence of a blast is determined. Is stored, and the signal is output to the controller.The controller reduces the explosion by lowering the welding output to the joint of the welding work only when receiving the explosion signal from the explosion generation memory. Flying can be prevented from occurring.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a projection welding apparatus according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing an example of a resistance value waveform of projection welding.

FIG. 3 is a characteristic diagram showing an example of an actually measured value of a resistance value waveform of projection welding.

FIG. 4 is a block diagram showing a projection welding apparatus according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing a projection welding apparatus according to a third embodiment of the present invention.

FIG. 6 is a block diagram showing a projection welding apparatus according to a fourth embodiment of the present invention.

FIG. 7 is a block diagram showing a projection welding apparatus according to a fifth embodiment of the present invention.

FIG. 8 is a block diagram showing a projection welding apparatus according to a sixth embodiment of the present invention.

FIG. 9 is a block diagram showing a projection welding apparatus according to a seventh embodiment of the present invention.

FIG. 10 is a characteristic diagram showing an example of a voltage waveform of projection welding.

FIG. 11 is a characteristic diagram showing an example of an actually measured value of a voltage waveform of projection welding.

FIG. 12 is a block diagram showing a projection welding apparatus according to an eighth embodiment of the present invention.

FIG. 13 is a block diagram showing a projection welding apparatus according to a ninth embodiment of the present invention.

FIG. 14 is a block diagram showing a projection welding apparatus according to a tenth embodiment of the present invention.

FIG. 15 is a block diagram showing a projection welding apparatus according to an eleventh embodiment of the present invention.

FIG. 16 is a block diagram showing a projection welding apparatus according to a twelfth embodiment of the present invention.

FIG. 17 is a block diagram showing a projection welding apparatus according to a thirteenth embodiment of the present invention.

FIG. 18 is a schematic view showing a joint of projection welding.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rectifier 2 Control element 3 Transformer 4 Rectifier 5 Current detector 6 Voltage detector 7 Resistance calculator 8 Sequence setter 9 Time setter 10 Average resistance calculator 11 Reference resistance setter 12 Comparator 13 Explosion indicator 14 Controller 15 Maximum Resistance Calculator 16 Resistance Differential Calculator 17 Reference Resistance Differential Setter 18 Average Resistance Calculator 19 Maximum Resistance Calculator 20 Resistance Differential Calculator 21 Average Voltage Calculator 22 Reference Voltage Setter 23 Maximum Voltage Calculator 24 Voltage Differential Calculation Device 25 Reference voltage derivative setting device 26 Average voltage calculator 27 Maximum voltage calculator 28 Voltage derivative calculator 29 Explosion generation storage device 30 Controller 50 Welding work

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor, Watanabe, Chiba 1006, Kazuma, Kazuma, Osaka, Japan Matsushita Electric Industrial Co., Ltd. 72) Inventor Makoto Ryudo 1006 Kadoma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (26)

[Claims] 1. A projection welding method for joining by utilizing resistance heat generated when a current is intensively applied to a joint portion of a welding work, wherein an average resistance for a certain period from the end of energization exceeds a reference value. A projection welding method, which determines that a blast has occurred, and indicates that a blast has occurred. 2. A projection welding method for joining by utilizing resistance heat generated when a current is intensively applied to a joint portion of a welding work, wherein a maximum resistance for a certain period from the end of energization exceeds a reference value. A projection welding method comprising: judging that a blast has occurred, and displaying that a blast has occurred. 3. A projection welding method for joining by utilizing resistance heat generated when a current is intensively applied to a joint portion of a welding work, wherein a differential value of a resistance value for a certain period from the end of energization is used as a reference. A projection welding method characterized by determining that a blast has occurred when a value is exceeded, and displaying that a blast has occurred. 4. A projection welding method for joining by utilizing resistance heat generated when current is intensively applied to a joint portion of a welding work, wherein when an average resistance during an energization period exceeds a reference value, the explosion occurs. A projection welding method characterized by determining that a flying has occurred and displaying that a blast has occurred. 5. A projection welding method for joining by utilizing resistance heat generated when a current is intensively applied to a joint portion of a welding work, wherein when a maximum resistance during an energization period exceeds a reference value, the explosion occurs. A projection welding method characterized by determining that a flying has occurred and displaying that a blast has occurred. 6. A projection welding method for joining by utilizing resistance heat generated when a current is intensively applied to a joint portion of a welding work, wherein a differential value of a resistance value during an energization period exceeds a reference value. A projection welding method characterized by sometimes determining that a blast has occurred and displaying that a blast has occurred. 7. A projection welding method for joining by utilizing resistance heat generated when a current is intensively applied to a joint portion of a welding work, wherein an average voltage for a certain period from the end of energization exceeds a reference value. A projection welding method comprising: judging that a blast has occurred, and displaying that a blast has occurred. 8. A projection welding method for joining by utilizing resistance heat generated when a current is intensively applied to a joint portion of a welding work, wherein a maximum voltage for a certain period from the end of energization exceeds a reference value. A projection welding method, which determines that a blast has occurred, and indicates that a blast has occurred. 9. A projection welding method for joining by utilizing resistance heat generated when current is intensively applied to a joint of a welding work, wherein a differential value of a voltage value for a certain period from the end of energization is used as a reference. A projection welding method characterized by determining that a blast has occurred when a value is exceeded, and displaying that a blast has occurred. 10. A projection welding method for joining by utilizing resistance heat generated when current is intensively applied to a joint portion of a welding work, wherein when an average voltage during an energization period exceeds a reference value, the A projection welding method characterized by determining that a flying has occurred and displaying that a blast has occurred. 11. A projection welding method for joining by utilizing resistance heat generated when a current is intensively applied to a joint portion of a welding work, wherein when a maximum voltage during an energization period exceeds a reference value, an explosion occurs. A projection welding method characterized by determining that a flying has occurred and displaying that a blast has occurred. 12. A projection welding method for joining by utilizing resistance heat generated when a current is intensively applied to a joint portion of a welding work, wherein a differential value of a voltage value during an energization period exceeds a reference value. A projection welding method characterized by sometimes determining that a blast has occurred and displaying that a blast has occurred. 13. A projection welding method for joining by utilizing resistance heat generated when a current is intensively applied to a joint portion of a welding work, wherein an average resistance for a certain period from the end of energization exceeds a reference value. A projection welding method comprising: determining that a blast has occurred, displaying that a blast has occurred, and lowering a welding output. 14. A current detector and a voltage detector for detecting a current and a voltage at a joint portion of a welding work, and a resistance calculator for inputting detection signals of the current detector and the voltage detector and calculating a resistance value. A sequence setting device for setting a sequence of welding current, a setting signal for inputting a setting signal of the sequence setting device, a time setting device for setting a time from the end of energization, an output signal of the resistance calculator and the time An output signal of the setting device is input, an average resistance calculator that calculates an average resistance for a certain period after the end of energization set by the time setting device, and a reference resistance setting device that sets a reference resistance value.
Input the output signal of the average resistance calculator and the output signal of the reference resistance setter, and compare the magnitude relationship between the two,
A comparator that outputs a blast generation signal when the output resistance value of the average resistance calculator exceeds the reference resistance value of the reference resistance setting device; and a blast generation signal that receives the output signal of the comparator. A projection welding device equipped with a blast indicator that indicates only when a blast has occurred. 15. A current detector and a voltage detector for detecting a current and a voltage at a joint portion of a welding work, and a resistance calculator for inputting detection signals of the current detector and the voltage detector and calculating a resistance value. A sequence setting device for setting a sequence of welding current, a setting signal for inputting a setting signal of the sequence setting device, a time setting device for setting a time from the end of energization, an output signal of the resistance calculator and the time Inputting the output signal of the setting device, a maximum resistance calculator for calculating the maximum resistance for a certain period after the energization set by the time setting device, a reference resistance setting device for setting a reference resistance value,
Input the output signal of the maximum resistance calculator and the output signal of the reference resistance setter, and compare the magnitude relationship between the two,
There is a comparator that outputs a blast generation signal when the output resistance value of the maximum resistance calculator exceeds the reference resistance value of the reference resistance setting device, and a blast generation signal is received upon receiving the output signal of the comparator. A projection welding device equipped with a blast indicator that indicates only when a blast has occurred. 16. A current detector and a voltage detector for detecting a current and a voltage at a joint of a welding work, and a resistance calculator for inputting detection signals of the current detector and the voltage detector to calculate a resistance value. A sequence setting device for setting a sequence of welding current, a setting signal for inputting a setting signal of the sequence setting device, a time setting device for setting a time from the end of energization, an output signal of the resistance calculator and the time A resistance differential calculator for inputting an output signal of a setting device and calculating a differential value of a resistance value for a certain period after the energization set by the time setting device, and a reference resistance differential setting for setting a reference resistance differential value And an output signal of the resistance differential calculator and an output signal of the reference resistance setting device, and compare the magnitude relation between the two. The output differential value of the resistance differential calculator is the reference resistance differential value. Setting A comparator for outputting a blast generation signal when the reference resistance differential value of the constant meter is exceeded, and receiving an output signal of the comparator and displaying that a blast has occurred only when there is a blast generation signal. Projection welding equipment equipped with a blast indicator. 17. A current detector and a voltage detector for detecting a current and a voltage at a joint portion of a welding work, and a resistance calculator for inputting detection signals of the current detector and the voltage detector and calculating a resistance value. And, a sequence setting device that sets a sequence of welding energization, an output signal of the resistance calculator and an output signal of the sequence setting device are input, and an average resistance calculator that calculates an average resistance during the energization period, A reference resistance setting device for setting a reference resistance value, and an output signal of the average resistance calculator and an output signal of the reference resistance setting device are input, and a magnitude relationship between the two is compared. A comparator that outputs a blast generation signal when the output resistance value exceeds the reference resistance value of the reference resistance setting device, and receives the output signal of the comparator, and only when there is a blast generation signal, the blast Table that occurred A projection welding device provided with a blast indicator shown. 18. A current detector and a voltage detector for detecting a current and a voltage at a joint portion of a welding work, and a resistance calculator for inputting detection signals of the current detector and the voltage detector to calculate a resistance value. And, a sequence setting device for setting a sequence of welding energization, a maximum resistance calculator for inputting an output signal of the resistance calculator and an output signal of the sequence setting device, and calculating a maximum resistance during an energization period. A reference resistance setting device for setting a reference resistance value, an output signal of the maximum resistance calculator and an output signal of the reference resistance setting device are input, and the magnitude relation between the two is compared. A comparator that outputs a blast generation signal when the output resistance value exceeds the reference resistance value of the reference resistance setting device, and receives the output signal of the comparator, and only when there is a blast generation signal, the blast Table that occurred A projection welding device provided with a blast indicator shown. 19. A current detector and a voltage detector for detecting a current and a voltage at a joint portion of a welding work, and a resistance calculator for inputting detection signals of the current detector and the voltage detector to calculate a resistance value. And a sequence setting device for setting a welding energization sequence, and a resistance differential resistance for inputting an output signal of the resistance calculator and an output signal of the sequence setting device to calculate a differential value of a resistance value during an energization period. A calculator, a reference resistance differential setter for setting a reference resistance differential value, and an output signal of the resistance differential resistance calculator and an output signal of the reference resistance setter are input, and the magnitude relation between the two is compared. A comparator that outputs a blast generation signal when an output resistance differential value of the resistance differential resistance calculator exceeds a reference resistance differential value of the reference resistance differential setter; Generated signal A projection welding device provided with a blast indicator that indicates that a blast has occurred only when there is a blast. 20. A voltage detector for detecting a voltage at a joint portion of a welding work, a sequence setting device for setting a sequence of welding energization, and a setting signal of the sequence setting device, and a time from the end of energization. A time setting device for setting an output signal of the voltage detector and an output signal of the time setting device, and an average voltage for calculating an average voltage for a certain period after the end of energization set by the time setting device. A calculator, a reference voltage setter for setting a reference voltage value, and an output signal of the average voltage calculator and an output signal of the reference voltage setter. A comparator that outputs a blast generation signal when the output voltage value of the voltage calculator exceeds the reference voltage value of the reference voltage setting device, and only when there is a blast generation signal after receiving the output signal of the comparator. , Explosion occurred A projection welding apparatus provided with a blast indicator for displaying the fact. 21. A voltage detector for detecting a voltage at a joint portion of a welding work, a sequence setting device for setting a sequence of welding energization, and a setting signal of the sequence setting device, and a time from the end of energization. A time setting device for setting a maximum voltage for inputting an output signal of the voltage detector and an output signal of the time setting device, and calculating a maximum voltage for a certain period after energization set by the time setting device. A calculator, a reference voltage setting device for setting a reference voltage value, and an output signal of the maximum voltage calculator and an output signal of the reference voltage setting device, and a magnitude relationship between the two is compared. A comparator that outputs a blast generation signal when the output voltage value of the voltage calculator exceeds the reference voltage value of the reference voltage setting device, and only when there is a blast generation signal after receiving the output signal of the comparator. , Explosion occurred A projection welding apparatus provided with a blast indicator for displaying the fact. 22. A voltage detector for detecting a voltage at a joint portion of a welding work, a sequence setting device for setting a sequence of welding energization, and a setting signal of the sequence setting device, and a time from the end of energization. A time setting device for setting the output signal of the voltage detector and the output signal of the time setting device, and calculate a differential value of a voltage value for a certain period after the end of energization set by the time setting device. A voltage derivative calculator, a reference voltage derivative setter for setting a reference voltage derivative value, and an output signal of the voltage derivative calculator and an output signal of the reference voltage derivative setter. Performing a comparison, a comparator that outputs a blast generation signal when the output voltage differential value of the voltage differential calculator exceeds the reference voltage differential value of the reference voltage differential setting device, and receives the output signal of the comparator; Explosion signal A projection welding device provided with a blast indicator that indicates that a blast has occurred only when there is a blast. 23. A voltage detector for detecting a voltage at a joint portion of a welding work, a sequence setting device for setting a welding energizing sequence, and an output signal of the voltage detector and an output signal of the sequence setting device. An average voltage calculator for calculating an average voltage during the energization period, a reference voltage setter for setting a reference voltage value, and an output signal of the average voltage calculator and an output signal of the reference voltage setter are input. Then, the magnitude relationship between the two is compared, a comparator that outputs a blast generation signal when the output voltage value of the average voltage calculator exceeds the reference voltage value of the reference voltage setting device, and a comparator of the comparator A projection welding apparatus comprising: a blast indicator that receives an output signal and displays that a blast has occurred only when a blast generation signal is received. 24. A voltage detector for detecting a voltage at a joint portion of a welding work, a sequence setting device for setting a welding energizing sequence, an output signal of the voltage detector and an output signal of the sequence setting device. Then, a maximum voltage calculator for calculating a maximum voltage during the energization period, a reference voltage setting device for setting a reference voltage value, and an output signal of the maximum voltage calculator and an output signal of the reference voltage setting device are input. Then, a comparison of the magnitude relationship between the two, a comparator that outputs a blast generation signal when the output voltage value of the maximum voltage calculator exceeds the reference voltage value of the reference voltage setting device, and a comparator of the comparator A projection welding apparatus comprising: a blast indicator that receives an output signal and displays that a blast has occurred only when a blast generation signal is received. 25. A voltage detector for detecting a voltage at a joint portion of a welding work, a sequence setting device for setting a welding energizing sequence, and an output signal of the voltage detector and an output signal of the sequence setting device. A voltage derivative calculator for calculating a differential value of the voltage value during the energization period, a reference voltage derivative setter for setting a reference voltage derivative, an output signal of the voltage derivative calculator and a reference voltage setter. An output signal is input, a magnitude relationship between the two is compared, and a blast generation signal is output when the output voltage differential value of the voltage differential calculator exceeds the reference voltage differential value of the reference voltage differential setting device. A projection welding apparatus comprising: a comparator; and a blast indicator that receives an output signal of the comparator and indicates that a blast has occurred only when there is a blast generation signal. 26. A current detector and a voltage detector for detecting a current and a voltage at a joint portion of a welding work, and a resistance calculator for inputting detection signals of the current detector and the voltage detector and calculating a resistance value. A sequence setting device for setting a sequence of welding energization, a time setting device for inputting a setting signal of the sequence setting device and setting a time from the end of energization, an output signal of the resistance calculator and the time An output signal of the setting device is input, an average resistance calculator that calculates an average resistance for a certain period after the end of energization set by the time setting device, and a reference resistance setting device that sets a reference resistance value.
Input the output signal of the average resistance calculator and the output signal of the reference resistance setter, and compare the magnitude relationship between the two,
A comparator that outputs a blast generation signal when the output resistance value of the average resistance calculator exceeds the reference resistance value of the reference resistance setting device; and a blast generation signal that receives the output signal of the comparator. Only at the time of the explosion, a blast indicator that indicates that a blast has occurred, and at the start of welding, that there is no blast, and the output signal of the comparator is received. A blast generation storage device that stores the presence and absence of a blast and outputs the signal, and the output of the blast generation storage device, and only when the blast signal is received, the joining portion of the welding work And a controller for controlling so as to reduce the welding output to the projection welding apparatus.