WO2021199784A1

WO2021199784A1 - Welding control device and welding control method

Info

Publication number: WO2021199784A1
Application number: PCT/JP2021/006406
Authority: WO
Inventors: 好寿中塚; 山田　清治; 芳樹花田; 祐太原
Original assignee: 株式会社ナ・デックス
Priority date: 2020-04-03
Filing date: 2021-02-19
Publication date: 2021-10-07
Also published as: CN114616069A; JP7464262B2; JP2021159989A

Abstract

Provided is a welding control device capable of improving production efficiency and welding quality. One aspect of the present disclosure provides a welding control device used for a resistance welding machine comprising: a first electrode and a second electrode; a support part that supports the second electrode; a motor that moves the first electrode relative to the second electrode; and an encoder that outputs the amount of rotation of the motor. The welding control device comprises: a strain sensor that measures the strain of the support part; and a control unit that controls the resistance welding machine. The control unit has: a displacement amount detection unit that detects, during the execution of welding by the resistance welding machine, the amount of displacement of an inter-electrode distance between the first electrode and the second electrode on the basis of the amount of rotation of the motor output by the encoder and the strain of the support part output by the strain sensor; and an adjustment unit that adjusts, during the execution of the welding, a welding current of the resistance welding machine on the basis of the amount of the displacement.

Description

Welding control device and welding control method

Cross-reference of related applications

This international application claims priority based on Japanese Patent Application No. 2020-67779 filed with the Japan Patent Office on April 3, 2020, and Japanese Patent Application No. 2020-67779. The entire contents are incorporated in this international application by reference.

The present disclosure relates to a welding control device and a welding control method.

In a resistance welding device that welds a work (that is, a material to be welded) by supplying an electric current while pressurizing it with two electrodes, thermal expansion occurs in the work. Therefore, there is a possibility that the welding quality can be determined by observing the fluctuation of the distance between the electrodes during welding.

Therefore, as a method of confirming the welding quality by resistance welding, a method of detecting the displacement amount of the distance between electrodes and diagnosing the welding quality has been devised (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2016-203246

In the above-mentioned welding quality diagnosis method, quality diagnosis is performed after welding is completed, so if the welding quality is not satisfied, it is necessary to carry out rewelding. As a result, the production efficiency of the product decreases.

Further, in the above publication, a method of detecting the displacement amount of the distance between electrodes by the encoder of the motor and a method of detecting by the strain of the gun arm are individually disclosed. When the displacement amount is detected by the encoder, the accuracy of the displacement amount is insufficient because the displacement of the electrode supported by the gun arm is not included. Similarly, when the displacement amount is detected by the strain of the gun arm, the accuracy of the displacement amount is insufficient because the displacement of the electrode whose position is changed by the motor is not included.

One aspect of the present disclosure is preferably to provide a welding control device capable of improving production efficiency and welding quality.

One aspect of the present disclosure is a first electrode and a second electrode arranged so as to sandwich a work, a support portion for supporting the second electrode, a motor for moving the first electrode with respect to the second electrode, and a motor. It is a welding control device used in a resistance welding machine provided with an encoder that outputs the amount of rotation of the above. The welding control device includes a strain sensor configured to measure the strain of the support portion and a control unit configured to control the resistance welder.

The control unit determines the distance between the first electrode and the second electrode based on the amount of motor rotation output by the encoder and the strain of the support unit output by the strain sensor during welding by the resistance welder. It has a displacement amount detecting unit that detects the displacement amount, and an adjusting unit that adjusts the welding current of the resistance welding machine based on the displacement amount detected by the displacement amount detecting unit during welding by the resistance welding machine.

According to such a configuration, the influence of disturbance can be reduced by detecting the displacement amount of the distance between the electrodes during welding and adjusting the welding current in real time. Therefore, the welding quality can be improved. Further, since the displacement amount is detected based on the rotation amount of the motor by the encoder and the strain of the support portion by the strain sensor, the detection accuracy of the displacement amount can be improved. As a result, production efficiency and welding quality can be improved.

In one aspect of the present disclosure, the control unit may further include a thickness detection unit that detects the total thickness of the welded portion of the work from the amount of rotation of the motor. According to such a configuration, welding control using the total thickness of the work becomes possible. Therefore, the improvement of welding quality can be promoted.

In one aspect of the present disclosure, the control unit may further include a pressure detection unit that detects the actual pressure applied to the work from the strain of the support unit. According to such a configuration, welding control using the actual pressing force applied to the work becomes possible. Therefore, the improvement of welding quality can be promoted.

In one aspect of the present disclosure, the control unit includes a thickness detection unit that detects the total thickness of the welded portion of the work from the amount of rotation of the motor, and a pressure detection unit that detects the actual pressure applied to the work from the strain of the support portion. , And may further have. The adjusting unit may adjust at least one of the magnitude of the welding current and the energization time of the resistance welder based on the total thickness and the actual pressing force. According to such a configuration, the current value and the energization time suitable for improving the welding quality can be automatically set.

In one aspect of the present disclosure, the adjusting unit may cause the resistance welder to start welding based on the displacement amount detected by the displacement amount detecting unit. According to such a configuration, the control by the welding control device is stable, so that the welding quality can be improved.

In one aspect of the present disclosure, the adjusting unit may supply a pulse current to the resistance welder and detect the disturbance based on the displacement amount detected by the displacement amount detecting unit when the pulse current is supplied. With such a configuration, it is possible to confirm the presence or absence of welding defects.

Another aspect of the present disclosure is a first electrode and a second electrode arranged so as to sandwich the work, a support portion for supporting the second electrode, and a motor for moving the first electrode with respect to the second electrode. This is a welding control method using a resistance welding machine equipped with an encoder that outputs the amount of rotation of the motor.

The welding control method detects the amount of displacement of the distance between the first electrode and the second electrode based on the amount of rotation of the motor output by the encoder and the distortion of the support portion during welding by the resistance welder. It has a step of adjusting the welding current of the resistance welder based on the detected displacement amount during the execution of welding by the resistance welder.

According to such a configuration, the production efficiency and the welding quality can be improved by adjusting the welding current in real time and improving the detection accuracy of the displacement amount.

One aspect of the present disclosure may further include a step of detecting the total thickness at the welded portion of the work from the amount of rotation of the motor.

One aspect of the present disclosure may further include a step of detecting the actual pressing force applied to the work from the strain of the support portion.

One aspect of the present disclosure includes a step of detecting the total thickness at the welded portion of the work from the rotation amount of the motor, a step of detecting the actual pressing force applied to the work from the strain of the support portion, and the total thickness and the actual pressing force. It may further have a step of adjusting at least one of the magnitude of the welding current and the energization time of the resistance welder based on the above.

One aspect of the present disclosure may further include a step of causing the resistance welder to start welding based on the detected displacement amount.

One aspect of the present disclosure may further include a step of supplying a pulse current to the resistance welder and detecting disturbance based on the amount of displacement detected when the pulse current is supplied.

FIG. 1 is a block diagram schematically showing a configuration of a welding control device according to an embodiment. FIG. 2 is a schematic view showing a resistance welder according to the embodiment. FIG. 3 is a graph showing an example of changes in welding current and displacement amount over time. FIG. 4 is a graph showing an example of changes in welding current and displacement amount over time. FIG. 5 is a graph showing an example of changes in welding current and displacement amount over time. FIG. 6 is a graph showing an example of changes in welding current and displacement amount over time. FIG. 7 is a graph showing an example of changes in welding current, displacement amount, and actual pressing force over time. FIG. 8 is a graph showing an example of changes over time in the welding current and the amount of displacement. FIG. 9 is a graph showing an example of changes in welding current and displacement amount over time. FIG. 10 is a flow chart schematically showing the processing executed by the control unit. FIG. 11 is a schematic view showing a resistance welder in an embodiment different from that of FIG. FIG. 12 is a graph showing an example of changes in welding current and displacement amount over time.

1 ... Welding control device, 2 ... Strain sensor, 2A ... 1st strain sensor, 2B ... 2nd strain sensor, 3 ... Control unit, 4 ... Displacement amount detection unit, 5 ... Thickness detection unit, 6 ... Pressure detection unit, 7 ... Adjustment part, 10 ... Resistance welding machine, 11 ... 1st electrode, 12 ... 2nd electrode, 13 ... Support part, 14 ... Motor, 15 ... Transmitter, 16 ... Encoder, 17 ... Welding gun, 20 ... Resistance welding machine , 21 ... 1st electrode, 22 ... 2nd electrode, 23A ... 1st support, 23B ... 2nd support, 24 ... motor, 25 ... transmitter, 26 ... encoder, 27 ... welding gun.

Hereinafter, embodiments to which the present disclosure has been applied will be described with reference to the drawings.

[1. First Embodiment]
[1-1. composition]
The welding control device 1 shown in FIG. 1 is used for controlling the resistance welding machine 10 shown in FIG.

<Resistance welding machine>
The resistance welding machine 10 resistance welds the first plate P1 and the second plate P2 arranged as the work W in the thickness direction. The work W has a first plate P1 and a second plate P2 on which the first plate P1 is overlapped from above.

The resistance welder 10 includes a first electrode 11, a second electrode 12, a support portion 13, a motor 14, a transmitter 15, and an encoder 16. The first electrode 11, the second electrode 12, and the support portion 13 constitute a C-type welding gun 17.

The first electrode 11 is arranged above the work W. The second electrode 12 is arranged below the work W so as to sandwich the work W together with the first electrode 11 in the thickness direction. The first electrode 11 and the second electrode 12 each come into contact with the work W during welding. A welding current supplied from the welding control device 1 flows between the first electrode 11 and the second electrode 12 via the work W.

The support portion 13 is a gun yoke that supports the second electrode 12. The second electrode 12 projects upward from the tip end portion of the support portion 13. The support portion 13 holds the second electrode 12 in a fixed position (that is, height).

The motor 14 rotates the transmitter 15 to move the first electrode 11 in the vertical direction with respect to the second electrode 12. That is, the motor 14 changes the distance between the first electrode 11 and the second electrode 12 by moving the first electrode 11 in the vertical direction.

Further, the motor 14 applies pressure to the work W by the first electrode 11 and the second electrode 12 (that is, the resistance welder 10) by changing the distance between the first electrode 11 and the second electrode 12. Welding pressure) is adjusted.

The transmitter 15 converts the rotational motion of the motor 14 into a linear motion in the vertical direction of the first electrode 11. As the transmitter 15, for example, a ball screw is used.

The encoder 16 outputs the amount of rotation of the motor 14. Specifically, the encoder 16 outputs the amount of rotation of the motor 14 as the number of pulses to the welding control device 1. The encoder 16 may directly output the rotation amount of the motor 14 to the welding control device 1, or the rotation amount of the motor 14 to the welding control device 1 via a robot controller (not shown) included in the resistance welder 10. May be output.

The amount of rotation of the motor 14 and the vertical position (that is, the height) of the first electrode 11 correlate with each other. In particular, when the transmitter 15 is a ball screw, the amount of rotation of the motor 14 and the amount of displacement of the first electrode 11 have a linear relationship.

<Welding control device>
As shown in FIG. 1, the welding control device 1 includes a strain sensor 2 and a control unit 3.

(Strain sensor)
The strain sensor 2 is attached to the support portion 13. The strain sensor 2 is configured to measure the strain generated in the support portion 13 when the welding gun 17 is pressurized. As the strain sensor 2, for example, a piezoelectric sensor, a strain gauge, or the like can be used.

(Control unit)
The control unit 3 is electrically connected to the resistance welder 10 and is configured to control the resistance welder 10.

The control unit 3 is composed of, for example, a computer including a microprocessor, a storage medium such as RAM and ROM, and an input / output unit. The control unit 3 includes a displacement amount detection unit 4, a thickness detection unit 5, a pressure detection unit 6, and an adjustment unit 7.

(Displacement amount detection unit)
The displacement amount detecting unit 4 describes the rotational position of the motor 14 output directly from the encoder 16 or via the robot controller and the distortion of the support unit 13 output by the strain sensor 2 during the execution of welding by the resistance welding machine 10. The amount of displacement of the distance between the first electrode 11 and the second electrode 12 is detected based on the above.

Specifically, when the work W expands during welding, the first electrode 11 is pushed up. As a result, the motor 14 rotates via the transmitter 15. The displacement amount detecting unit 4 acquires the rotation amount of the motor 14 from the encoder 16 and uses a function of the rotation amount of the motor 14 and the position of the first electrode 11, so that the displacement amount of the position of the first electrode 11 Is detected.

Further, when the work W expands, the second electrode 12 is pushed down. As a result, the support portion 13 is distorted. The displacement amount detecting unit 4 acquires the strain of the support portion 13 from the strain sensor 2, and uses a function of the strain of the support portion 13 and the position of the second electrode 12 to displace the position of the second electrode 12. Detect the amount.

The displacement amount detecting unit 4 detects the distance between the first electrode 11 and the second electrode 12 by adding the displacement amount at the position of the first electrode 11 and the displacement amount at the position of the second electrode 12. do. Further, the displacement amount detecting unit 4 continuously detects the distance between the electrodes from the start to the end of welding.

FIG. 3 shows an example of displacement amount detection. In FIG. 3, the displacement amount D1 of the first electrode 11 due to the rotation amount of the motor 14 detected when welding is performed with the welding current C constant, and the displacement amount D2 of the second electrode 12 due to the distortion of the support portion 13. And the time change of the displacement amount D3 of the distance between the electrodes due to the rotation amount of the motor 14 and the distortion of the support portion 13 is shown. The waveform of the displacement amount D3 of the inter-electrode distance is substantially the same as the waveform of the displacement amount D0 of the inter-electrode distance measured by the laser measuring instrument.

(Thickness detector)
The thickness detection unit 5 detects the total thickness of the work W at the welded portion from the amount of rotation of the motor 14. The total thickness is detected before the start of welding by the resistance welder 10 or during the execution of welding.

Specifically, the thickness detection unit 5 sets the work W as the first electrode at the time of welding and the reference position of the first electrode 11 when the second electrode 12 is pressurized by the first electrode 11 in the absence of the work W. The total thickness of the work W at the welded portion is calculated from the difference from the position of the first electrode 11 when pressurized by 11.

(Pressure detector)
The pressure detection unit 6 detects the actual pressure applied to the work W from the strain of the support unit 13. The actual pressing force is detected before the start of welding by the resistance welder 10 or during the execution of welding.

Specifically, the pressure detection unit 6 calculates the actual applied pressure on the current work W from the magnitude of strain (that is, the output of the strain sensor 2) using a well-known stress-strain curve and Hooke's law. do. Since a relatively high pressing force acts between the first electrode 11 and the second electrode 12, the support portion 13 is deformed in the elastic deformation region of the stress-strain curve. Therefore, according to Hooke's law, strain and actual pressure are proportional.

(Adjustment section)
The adjusting unit 7 is a resistance welder 10 (based on the displacement amount of the distance between the electrodes detected by the displacement amount detecting unit 4, the total thickness detected by the thickness detecting unit 5, and the actual applied pressure detected by the pressure detecting unit 6). That is, the welding current of the welding gun 17) is adjusted.

Specifically, the adjusting unit 7 adjusts the welding current so that the rate of change of the displacement amount of the distance between the electrodes becomes an appropriate magnitude during the execution of welding by the resistance welding machine 10. FIG. 4 shows the displacement amount D11 of the distance between the electrodes in the first case welded with the first current C11 and the distance between the electrodes in the second case welded with the second current C12 smaller than the first current C11. An example of the time change with the displacement amount D12 is shown.

In FIG. 4, the displacement amount D11 of the first case has a larger increase rate than the displacement amount D12 of the second case. Further, the diameter of the welding nugget obtained in the first case is larger than the diameter of the welding nugget obtained in the second case.

Further, in FIG. 5, the displacement amount D13 of the distance between the electrodes in the third case welded with the third current C13 and the distance between the electrodes in the fourth case welded with the fourth current C14 larger than the third current C13. An example of the time change with the displacement amount D14 of the distance is shown.

In FIG. 5, the displacement amount D14 of the fourth case has a larger rate of change than the displacement amount D13 of the third case. Further, in the third case, scattering does not occur during welding, while in the fourth case, scattering occurs.

Based on such a relationship, the adjusting unit 7 targets the rate of change of the displacement amount at which a welding nugget having a sufficient size is formed and the occurrence of scattering is suppressed during welding, and the welding current of the welding gun 17 is changed. Set the size. By suppressing the occurrence of scattering in this way, effects such as improvement of welding quality, improvement of working environment, and reduction of man-hours for cleaning the work W in the subsequent process can be obtained.

Further, the adjusting unit 7 adjusts the energizing time after the displacement amount of the distance between the electrodes is saturated during the execution of welding by the resistance welding machine 10. FIG. 6 shows the displacement amount D15 of the distance between the electrodes in the fifth case in which the fifth current C15 is energized, and the displacement amount of the distance between the electrodes in the sixth case in which the sixth current C16 having the same magnitude as the fifth current C15 is energized. An example of time change with D16 is shown.

In the fifth case, the welding current is still energized even after the displacement amount D15 is saturated. On the other hand, in the sixth case, the welding current is cut off immediately after the displacement amount D16 is saturated. Further, the diameter of the welding nugget obtained in the fifth case is larger than the diameter of the welding nugget obtained in the sixth case. Based on such a relationship, the adjusting unit 7 sets the energization time of the welding current after the displacement amount is saturated so that the welding nugget having a sufficient size is formed.

Further, the adjusting unit 7 adjusts the magnitude of the welding current according to the actual pressing force applied to the work W. FIG. 7 shows a displacement amount D17 of the distance between the electrodes in the seventh case in which the seventh current C17 is energized, and a displacement amount D18 of the distance between the electrodes in the eighth case in which the eighth current C18 larger than the seventh current C17 is energized. An example of the time change of is shown. Further, FIG. 7 shows the actual pressing force S17 in the seventh case and the actual pressing force S18 in the eighth case.

In the seventh case, the displacement amount D17 and the actual pressing force S17 change smoothly. On the other hand, in the eighth case, the displacement amount D18 and the actual pressing force S18 are sharply reduced. Further, in the seventh case, scattering does not occur during welding, while in the eighth case, scattering occurs. Based on such a relationship, the adjusting unit 7 adjusts the magnitude of the welding current while monitoring the actual pressing force so that scattering does not occur during welding.

Further, the adjusting unit 7 determines the effective welding current magnitude (for example, welding start current value, minimum current value, maximum current value, current change rate, etc.) and energization time (for example, minimum) based on the total thickness and the actual pressing force. Set the energization time, maximum energization time, etc.). The magnitude of the welding current and the energizing time are set before the start of welding by the resistance welding machine 10 or during the execution of welding.

Further, the adjusting unit 7 causes the resistance welding machine 10 to start welding based on the displacement amount detected by the displacement amount detecting unit 4. Specifically, the adjusting unit 7 waits for welding by the resistance welding machine 10 until the change in the magnitude of the displacement amount and / or the change speed of the displacement amount becomes small (that is, the displacement amount becomes stable). After the displacement amount is stabilized, the adjusting unit 7 causes the resistance welding machine 10 to start welding. A current may or may not be supplied to the standby resistance welder 10.

Further, the adjusting unit 7 supplies a pulse current to the resistance welding machine 10, and detects a disturbance based on the displacement amount detected by the displacement amount detecting unit 4 when the pulse current is supplied. The disturbance is, for example, a gap in the work W, a foreign substance being caught in the work W, a scraping, or the like.

For example, as shown in FIG. 8, when the rate of change of the displacement amount D21 decreases when the pulse current PC is energized before the welding current C21 is energized, the adjusting unit 7 moves the first plate P1 and the second plate of the work W. It is determined that a gap has been generated between P2 and P2.

Further, for example, as shown in FIG. 9, when the displacement amount D22 decreases when the pulse current PC is energized before the welding current C22 is energized, the adjusting unit 7 determines that foreign matter is caught or edged. do.

[1-2. process]
Hereinafter, an example of the process executed by the control unit 3 of the welding control device 1 will be described with reference to the flow chart of FIG.

In this process, first, the control unit 3 energizes the resistance welding machine 10 with a welding current and starts welding (step S100). After the start of welding, the control unit 3 detects the amount of displacement of the distance between the first electrode 11 and the second electrode 12 (step S110). Subsequently, the control unit 3 adjusts the welding current of the resistance welding machine 10 based on the detected displacement amount (step S120).

During the continuation of welding, the control unit 3 determines whether or not the welding is completed (that is, whether the welding point has reached the end point) (step S130). When the welding is completed (S130: YES), the control unit 3 ends the process. When the welding is not completed (S130: NO), the control unit 3 repeats the detection of the displacement amount and the adjustment of the welding current until the welding is completed.

[1-3. Welding control method]
The welding control method of this embodiment is executed by the control unit 3. That is, in the welding control method of the present embodiment, the step of starting the welding on the resistance welding machine 10, the step of detecting the displacement amount of the distance between the electrodes, and the welding current of the resistance welding machine 10 are adjusted based on the displacement amount. The magnitude of the welding current of the resistance welding machine 10 based on the steps, the step of detecting the total thickness at the welded portion of the work W, the step of detecting the actual pressing force applied to the work W, and the total thickness and the actual pressing force. It also has a step of adjusting at least one of the energization time and a step of detecting disturbance based on the amount of displacement.

[1-4. effect]
According to the embodiment described in detail above, the following effects can be obtained.

(1a) The influence of disturbance can be reduced by detecting the displacement amount of the distance between the electrodes during welding of the resistance welding machine 10 and adjusting the welding current in real time. Therefore, the welding quality can be improved. Further, since the displacement amount is detected based on the rotation amount of the motor 14 by the encoder 16 and the strain of the support portion 13 by the strain sensor 2, the detection accuracy of the displacement amount can be improved. As a result, production efficiency and welding quality can be improved.

(1b) The thickness detection unit 5 enables welding control using the total thickness of the work W. Therefore, the improvement of welding quality can be promoted.

(1c) The pressure detection unit 6 enables welding control using the actual pressure applied to the work W. Therefore, the improvement of welding quality can be promoted.

(1d) By adjusting at least one of the magnitude of the welding current and the energizing time of the resistance welding machine 10 based on the total thickness and the actual pressing force, the current value and the energizing time suitable for improving the welding quality are automatically set. can do.

(1e) By starting the welding in the resistance welding machine 10 based on the displacement amount detected by the displacement amount detecting unit 4, the control by the welding control device 1 is stabilized, and the welding quality can be improved.

(1f) By detecting the disturbance based on the displacement amount detected by the displacement amount detection unit 4 when the pulse current is supplied, it is possible to confirm the presence or absence of welding defects.

[2. Second Embodiment]
[2-1. composition]
The welding control device of the second embodiment is used for controlling the resistance welding machine 20 shown in FIG.

The resistance welder 20 resistance welds the first plate P1 and the second plate P2 arranged as the work W in the thickness direction. The resistance welder 20 includes a first electrode 21, a second electrode 22, a first support portion 23A, a second support portion 23B, a motor 24, a transmitter 25, and an encoder 26.

The first electrode 21, the second electrode 22, the first support portion 23A, and the second support portion 23B constitute an X-type welding gun 27. The first electrode 21, the second electrode 22, the motor 24, and the encoder 26 are the same as the first electrode 11, the second electrode 12, the motor 14, and the encoder 16 of the resistance welder 10 of FIG.

The first support portion 23A is a gun arm that supports the first electrode 21. The first support portion 23A is configured to be swingable with respect to the second support portion 23B by the transmitter 25. The positions of the first electrode 21 and the work W and the second electrode 22 are adjusted by the swing of the first support portion 23A.

The second support portion 23B is a gun yoke that supports the second electrode 22. The transmitter 25 swings the first support portion 23A by the driving force of the motor 24. Therefore, the motor 24 moves the first electrode 21 with respect to the second electrode 22.

The welding control device of the present embodiment is the same as the welding control device 1 of the first embodiment except for the points described below.

In the present embodiment, the welding control device has a first strain sensor 2A for measuring the strain of the first support portion 23A and a second strain sensor 2B for measuring the strain of the second support portion 23B. Further, the displacement amount detection unit of the welding control device includes the rotation amount of the motor 24 output by the encoder 26, the strain of the first support portion 23A output by the first strain sensor 2A, and the first strain output by the second strain sensor 2B. 2 The amount of displacement of the distance between the first electrode 21 and the second electrode 22 is detected based on the strain of the support portion 23B.

Specifically, the displacement amount detecting unit includes the displacement amount of the first electrode 21 calculated from the rotation amount of the motor 24 and the displacement amount of the position of the first electrode 21 calculated from the strain of the first support unit 23A. , The distance between the first electrode 21 and the second electrode 22 is detected from the displacement amount of the position of the second electrode 22 calculated from the strain of the second support portion 23B.

FIG. 12 shows an example of displacement amount detection. FIG. 12 shows a time change of the displacement amount D3 of the distance between the electrodes detected by the displacement amount detecting unit when welding is performed with the welding current C constant. The waveform of the displacement amount D3 of the inter-electrode distance is substantially the same as the waveform of the displacement amount D0 of the inter-electrode distance measured by the laser measuring instrument.

In the present embodiment, one of the first strain sensor 2A and the second strain sensor 2B can be omitted. However, by using the two strain sensors, the accuracy of detecting the displacement amount can be improved.

[2-2. effect]
According to the embodiment described in detail above, the following effects can be obtained.

(2a) The accuracy of detecting the displacement amount can be improved even for the resistance welding machine 20 in which the first electrode 21 moves with respect to the second electrode 22 due to the swing of the first support portion 23A. As a result, production efficiency and welding quality can be improved.

[3. Other embodiments]
Although the embodiments of the present disclosure have been described above, it goes without saying that the present disclosure is not limited to the above-described embodiments, and various forms can be adopted.

(3a) In the welding control device of the above embodiment, the control unit does not necessarily have to have a thickness detection unit and a pressure detection unit.

(3b) In the welding control device of the above embodiment, the adjusting unit does not necessarily have to cause the resistance welder to start welding based on the displacement amount. Further, the adjusting unit does not necessarily have to detect the disturbance based on the displacement amount at the time of supplying the pulse current.

(3c) The welding control device of the above embodiment is a resistance welding machine that pressurizes the work W in the horizontal direction (that is, welds in a state where the first plate P1 and the second plate P2 are overlapped in the horizontal direction). It can also be used for.

(3d) In the welding control device of the above embodiment, both the first electrode and the second electrode are moved by the motor (for example, in the resistance welding machine 20 of the second embodiment, the second support portion 23B is also shaken by the motor 24. It can also be used in resistance welders (configured to move).

(3e) The functions of one component in the above embodiment may be dispersed as a plurality of components, or the functions of the plurality of components may be integrated into one component. Further, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above embodiment may be added or replaced with the configuration of the other embodiment. It should be noted that all aspects included in the technical idea specified from the wording described in the claims are embodiments of the present disclosure.

Claims

A first electrode and a second electrode arranged so as to sandwich a work, a support portion for supporting the second electrode, a motor for moving the first electrode with respect to the second electrode, and a rotation amount of the motor. It is a welding control device used in a resistance welding machine equipped with an encoder that outputs
A strain sensor configured to measure the strain of the support and
A control unit configured to control the resistance welder and
With
The control unit
During welding by the resistance welding machine, the electrodes of the first electrode and the second electrode are based on the amount of rotation of the motor output by the encoder and the strain of the support portion output by the strain sensor. Displacement amount detection unit that detects the displacement amount of the distance, and
An adjusting unit that adjusts the welding current of the resistance welding machine based on the displacement amount detected by the displacement amount detecting unit during the execution of welding by the resistance welding machine.
Welding control device.
The welding control device according to claim 1.
The control unit is a welding control device further comprising a thickness detection unit that detects the total thickness of the work at the welded portion from the rotation amount of the motor.
The welding control device according to claim 1 or 2.
The control unit is a welding control device further comprising a pressure detection unit that detects the actual pressure applied to the work from the strain of the support portion.
The welding control device according to claim 1.
The control unit
A thickness detection unit that detects the total thickness of the welded portion of the work from the amount of rotation of the motor,
A pressure detection unit that detects the actual pressure applied to the work from the strain of the support unit, and a pressure detection unit.
Have more
The adjusting unit is a welding control device that adjusts at least one of the magnitude of the welding current and the energization time of the resistance welding machine based on the total thickness and the actual pressing force.
The welding control device according to any one of claims 1 to 4.
The adjusting unit is a welding control device that causes the resistance welder to start welding based on the displacement amount detected by the displacement amount detecting unit.
The welding control device according to any one of claims 1 to 5.
The adjusting unit is a welding control device that supplies a pulse current to the resistance welding machine and detects disturbance based on the displacement amount detected by the displacement amount detecting unit when the pulse current is supplied.
A first electrode and a second electrode arranged so as to sandwich a work, a support portion for supporting the second electrode, a motor for moving the first electrode with respect to the second electrode, and a rotation amount of the motor. It is a welding control method using a resistance welding machine equipped with an encoder that outputs
During welding by the resistance welder, the amount of displacement of the distance between the first electrode and the second electrode is determined based on the amount of rotation of the motor output by the encoder and the strain of the support portion. The process of detection and
During the execution of welding by the resistance welder, the step of adjusting the welding current of the resistance welder based on the detected displacement amount, and
Welding control method.
The welding control method according to claim 7.
A welding control method further comprising a step of detecting the total thickness of the work at a welded portion from the amount of rotation of the motor.
The welding control method according to claim 7 or 8.
A welding control method further comprising a step of detecting an actual pressing force applied to the work from the strain of the support portion.
The welding control method according to claim 7.
A step of detecting the total thickness of the welded portion of the work from the amount of rotation of the motor, and
A process of detecting the actual pressing force applied to the work from the strain of the support portion, and
A step of adjusting at least one of the magnitude of the welding current and the energization time of the resistance welding machine based on the total thickness and the actual pressing force.
Further, a welding control method.
The welding control method according to any one of claims 7 to 10.
A welding control method further comprising a step of causing the resistance welding machine to start welding based on the detected displacement amount.
The welding control method according to any one of claims 7 to 11.
A welding control method further comprising a step of supplying a pulse current to the resistance welding machine and detecting a disturbance based on the displacement amount detected at the time of supplying the pulse current.