JP2022100216A - Electrode positional displacement detection device of resistance welding device - Google Patents

Abstract

To provide an electrode positional displacement detection device of a resistance welding device which can detect positional displacements of any of opposing two electrodes.SOLUTION: In a state where electrodes 1 of a resistance welding device attached to, for example, a manipulator of an industrial robot are in a prescribed position, grip members 4 which are brought into prescribed closed states with respect to the electrodes 1 in proper positions are moved simultaneously to external peripheral parts of the electrodes so as to grip both the opposing electrodes 1, and when the grip members 4 are not brought into the prescribed closed state, that is, when the grip members 4 are not closed due to displacements of the electrodes 1, it can be determined that any of the electrodes 1 is displaced. By this constitution, a displacement of any of the opposing two electrodes 1 can be also detected. It can be determined that the grip members 4 are not brought into the prescribed closed states from the fact that determination electrodes 8 arranged at, for example, turning tip parts of the grip members 4 are in non-energization states.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electrode misalignment detecting device of a resistance welding device, particularly a device for detecting an electrode misalignment of a resistance welding device that joins a plurality of members to be joined by pressurizing and energizing them.

Resistance welding, which is one of the joining methods, has advantages such as low distortion, good appearance, and short welding time, and is widely adopted in the automobile industry, especially in the manufacture of vehicle bodies. As is well known, resistance welding, which is also generally called spot welding, is performed mainly by melting Joule heat due to contact resistance between members to be joined to melt the members themselves to be joined. In order to efficiently increase this Joule heat, a plurality of (generally two) members to be joined are sandwiched between facing electrodes and pressurized and energized.

In mass-produced vehicle body manufacturing, a resistance welding device equipped with this counter electrode and a pressurizing device for the electrodes is attached to a manipulator of an industrial robot, and this robot is taught to perform resistance welding to various parts of the vehicle body. Generally, one of the counter electrodes is fixed and the other is movable. In mass-produced vehicle body manufacturing using such industrial robots, the position of the electrode (position in the radial direction of the electrode) is caused by the electrode colliding with another object or welding of the electrode to the member to be joined (base material). It may shift. In particular, if the electrodes do not face each other properly, there will be problems such as a decrease in energization efficiency and poor welding, and a decrease in spatterless function and spattering.

Therefore, in Patent Document 1 below, a conductive detection plate is arranged in the movable range of the robot, and an allowable hole into which an electrode can be inserted is provided in the detection plate so that the continuity between the upper electrode and the detection plate can be detected. Configure. Then, first, the lower electrode is inserted into the allowable hole, and then the robot is taught so that the upper electrode is inserted into the allowable hole. If the lower electrode is displaced with respect to the upper electrode in the radial direction of the electrode and the amount of the displacement is larger than the set gap between the allowable hole and the upper electrode, the upper electrode abuts on the detection plate at the peripheral edge of the allowable hole. Therefore, conduction occurs between the two, and as a result, when the upper electrode and the detection plate are conducting, it can be seen that the upper electrode is displaced with respect to the lower electrode.

Japanese Unexamined Patent Publication No. 2011-51003

However, the electrode misalignment detecting device of the resistance welding apparatus described in Patent Document 1 cannot detect that the lower electrode is misaligned. In principle, electrode misalignment can occur in both the upper and lower electrodes, so an electrode misalignment detection device for resistance welding devices that can detect misalignment in both the lower and upper electrodes is available. desired.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an electrode misalignment detecting device for a resistance welding device capable of detecting any misalignment of two opposing electrodes. be.

The electrode position deviation detection device of the resistance welding device for achieving the above object is
In a resistance welding device that joins multiple members to be joined by sandwiching them between facing electrodes and applying pressure to them.
The electrode misalignment detecting means is provided with an electrode misalignment detecting means for detecting the misalignment of the outer peripheral portion of each electrode while the resistance welding device is in a predetermined position and is simultaneously approached to the outer peripheral portions of both of the facing electrodes. Is moved to the outer peripheral side of both of the electrodes so as to sandwich the electrodes from both outer sides in the radial direction of the opposing electrodes while the resistance welding device is in the predetermined position, and each electrode is in an appropriate position. A pinching member that is in a predetermined closed state, a signal generating means that outputs a moving state signal according to the moving state of the pinching member toward the outer peripheral portion of the electrode, and a moving state signal of the signal generating means. Based on the above, a non-closed state detecting means for detecting that the sandwiching member moved to the outer peripheral portion side of the electrode is not in the predetermined closed state, and
The non-closed state detecting means is provided with a misalignment determining means for determining that any of the electrodes is misaligned when the sandwiching member is detected to be in a state other than the predetermined closed state. And.

According to this configuration, for example, in a state where a resistance welding device attached to a manipulator of an industrial robot is in a predetermined position, it is simultaneously moved to the outer peripheral side of each electrode so as to sandwich both of the opposing electrodes. Since the sandwiching member is not in a predetermined closed state, that is, the sandwiching member is not completely closed due to the misalignment of the electrodes, it can be determined that any of the electrodes is misaligned. Any misalignment of any of the two electrodes can be detected.

In another configuration of the present invention, the signal generating means is provided on the sandwiching member, and when the sandwiching member moved to the outer peripheral side of the electrode is in the predetermined closed state, the determination electrode comes into contact with each other. And the determination electrode current applying means for applying a current between the determination electrodes in a state where the sandwiching member is moved to the outer peripheral portion side of the electrode, and the non-closed state detecting means applies the determination electrode current. A non-energized detecting means for detecting that the determination electrodes are in a non-energized state while a current is applied between the determination electrodes by the means is provided, and the non-energized detection means causes the determination electrodes to be in a non-energized state. It is characterized in that it is determined that the sandwiching member is in a state other than the predetermined closed state.

According to this configuration, since the determination electrode to be contacted in the predetermined closed state of the sandwiching member is in the non-energized state, it is determined that the sandwiching member is not in the predetermined closed state, that is, it is not completely closed due to the displacement of the electrodes. This makes it possible to reliably detect the misalignment of the two opposing electrodes.

Another aspect of the present invention is in a resistance welding apparatus in which a plurality of members to be joined are sandwiched between facing electrodes and pressurized and energized to join the members to be joined.
The resistance welding device is provided with an electrode misalignment detecting means for detecting the misalignment of the outer peripheral portion or the tip portion of each electrode by being approached at the same time as the outer peripheral portions or the tip portions of both of the facing electrodes in a predetermined position. The electrode misalignment detecting means is located radially outside the facing electrode with the resistance welding device in the predetermined position, and the distance in the electrode radial direction to the outer peripheral portion or the tip portion of each electrode is non-contact. An electrode distance sensor that detects the state, and a misalignment determining means that determines that the electrode is misaligned when the distance in the electrode radial direction to the electrode detected by the electrode distance sensor is not more than a predetermined distance. It is characterized by having.

According to this configuration, for example, a resistance welding device attached to a manipulator of an industrial robot is simultaneously approached to the outer peripheral portion or the tip portion of both of the opposing electrodes in a predetermined position, and the diameter of each electrode is large. The electrode distance sensor located outside the direction detects the distance in the radial direction of the electrode to each electrode in a non-contact state, and when the detected distance in the radial direction of the electrode to each electrode is equal to or less than a predetermined distance, the electrode is Since it can be determined that the electrodes are misaligned, any misalignment of the two opposing electrodes can be detected.

Another configuration of the present invention is arranged between the tip and the electrode distance sensor when the electrode distance sensor detects the distance in the electrode radial direction to the tip of each electrode. An electrode position reflecting member that is moved in the radial direction of the electrode according to the position is provided, and the electrode distance sensor detects the distance in the electrode radial direction to the electrode position reflecting member to reach the tip of the electrode. It is characterized by detecting a distance.

According to this configuration, for example, when the tip of the electrode has a spherical shape or a tapered shape, it is difficult to detect the distance in the radial direction of the electrode to the tip, but the position of the tip is in the radial direction of the electrode. The distance in the electrode radial direction to the outer peripheral portion of the electrode position reflecting member reflected by the movement to the electrode position can be detected relatively easily by the electrode distance sensor, and the distance in the electrode radial direction to the outer peripheral portion of the electrode can be detected by the electrode distance sensor. It is possible to shorten the configuration of the electrode position deviation detecting means in the electrode extension direction as compared with the case of detecting with.

As described above, according to the present invention, since it is possible to detect the positional deviation of any of the two opposing electrodes, it is possible to secure and improve the resistance welding quality especially in applications such as mass production vehicle body manufacturing. Will be.

It is a perspective view which shows the 1st Embodiment of the electrode position deviation detection apparatus of the resistance welding apparatus of this invention. It is a partial cross-sectional plan view of the electrode position deviation detection device of FIG. It is explanatory drawing of the operation of the electrode position deviation detection apparatus of FIG. 1 and FIG. It is a flowchart of the arithmetic processing performed by the control device of the electrode position deviation detection device of FIG. It is a schematic block diagram which shows the 2nd Embodiment of the electrode position deviation detection apparatus of the resistance welding apparatus of this invention. It is a flowchart of the arithmetic processing performed by the control device of the electrode position deviation detection device of FIG. It is a schematic block diagram which shows the 1st modification of the position deviation detection apparatus of FIG. It is a schematic block diagram which shows the 2nd modification of the position deviation detection apparatus of FIG. It is a partial sectional plan view which shows the 3rd Embodiment of the electrode position deviation detection apparatus of the resistance welding apparatus of this invention. It is explanatory drawing of the operation of the electrode position deviation detection apparatus of FIG. It is a flowchart of the arithmetic processing performed by the control device of the electrode position deviation detection device of FIG.

Hereinafter, embodiments of the electrode position deviation detecting device of the resistance welding device of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a main part of the first embodiment of the electrode position deviation detecting device 2 of the present invention, and FIG. 2 is a partial cross-sectional plan view of the electrode position deviation detecting device 2 of FIG. 1 (a) and 2 (a) show a state in which the sandwiching member 4 described later is open, and FIGS. 1 (b) and 2 (b) show a state in which the sandwiching member 4 is closed. In the resistance welding apparatus of this embodiment, similarly to the existing resistance welding apparatus, a plurality of members to be joined (not shown) are sandwiched between the upper and lower electrodes 1 shown in the figure, and the members are energized in a state of being pressurized by the electrodes 1. As a result, the region near the contact interface of the member to be welded itself is melted and solidified (solidified) and welded. Generally, one of the opposing electrodes 1 is fixed and the other is movable. Although these figures are included and the resistance welding device other than the electrode 1 is omitted in the following embodiment, the resistance welding device of this embodiment is, for example, an electrode, as in the general resistance welding device. It is configured to include a pressurizing device (usually also serving as a moving device for the electrode 1) of 1.

Further, the resistance welding apparatus of this embodiment is attached to a manipulator of an industrial robot (not shown), as in Patent Document 1. Since an industrial robot generally called a multi-axis robot can freely move the manipulator within a movable range by teaching, the resistance welding device and the electrode 1 attached to the manipulator can be controlled to various postures at various positions. Then, in that state, the member to be joined is sandwiched between the electrodes 1, and pressure welding is performed to perform resistance welding. Further, in this embodiment, as in Patent Document 1, the electrode 1 (resistance welding device) is moved and fixed to the position of the electrode position deviation detecting device 2 shown in the figure, and the electrode 1 is particularly moved and fixed in the radial direction of the electrode. Detects whether or not the position is displaced. This position is defined as a predetermined determination position (predetermined position). At this predetermined determination position, the electrodes 1 are fixed at predetermined proximity positions facing each other. Further, the operation control and determination of the electrode position deviation detecting device 2 are executed by the control device 3 having an arithmetic processing function. The control device 3 may be integrated with the resistance welding device or the control device of the industrial robot, or may be a separate body.

The electrode position deviation detecting device 2 is configured to include a sandwiching member 4 that is moved from both outer sides in the radial direction of each electrode 1 of the resistance welding device fixed at the predetermined determination position to the outer peripheral portion side of each electrode 1. To. The sandwiching member 4 of this embodiment is composed of two pairs of members extending in a direction substantially orthogonal to the extension direction of the electrode 1 on both outer sides in the radial direction of each electrode 1, and as shown in FIG. A pair is arranged for each of the electrodes 1 located above and below. As shown in FIG. 2B, for example, the sandwiching member 4 is predetermined with respect to the outer peripheral portion of the electrode 1 at an appropriate position in a state of being moved toward the electrode 1 so as to sandwich the electrode 1. A recess 7 having a semicircular cross section is provided so as to form a gap between the two. When the side where the recess 7 is located is defined as the tip end side of the sandwiching member 4, and the opposite side thereof is defined as the proximal end side, the determination electrode 8 is provided on the facing surface on the tip end side of the recess 7, and FIG. As clearly shown in b), the determination electrodes 8 facing each other are configured to abut against the electrode 1 at an appropriate position while the sandwiching member 4 is being moved so as to sandwich the electrode 1. .. The state of the sandwiching member 4 is defined as a predetermined closed state. Further, for example, the proximal ends of the two pairs of sandwiching members 4 arranged at the top and bottom of FIG. 1 are coupled by a coupling member 9 having a predetermined length in the extension direction of the electrode 1. Further, an arm member 10 extending in the extension direction of each sandwiching member 4 is continuously provided in the coupling member 9, and a rotation shaft 11 extending in the electrode extension direction is inserted through an intermediate portion of the arm member 10 in the extension direction. ing. A link member 12 is rotatably connected to an end portion of the arm member 10 opposite to the sandwiching member connecting side, and an end portion of the link member 12 opposite to the arm member connecting side is an advancing / retreating device 13. Is rotatably connected to the tip of the rod member 14 of the above. The rod member 14 of the advancing / retreating device 13 expands or contracts in the radial direction of the electrode 1 at an appropriate position, and the advancing / retreating device 13 is composed of, for example, an air cylinder.

As shown in FIG. 2A, when the rod member 14 of the advancing / retreating device 13 is extended, as shown in FIGS. 1A and 2A, the tip of each pair of sandwiching members 4 The portions are separated from each other, and the recesses 7 of the sandwiching members 4 are also opened. In this state, the electrode 1 of the resistance welding device is moved to, for example, a position shown in FIG. 1A, that is, a predetermined determination position and fixed, and in that state, the rod member 14 of the advancing / retreating device 13 is contracted. As a result, the arm member 10 and the sandwiching member 4 rotate around the rotation shaft 11 so that the tips thereof close with each other as the link member 12 rotates, and the pair of sandwiching members 4 rotate with respect to each other in the radial direction of the electrode 1. It is moved from both outer sides to the outer peripheral portion side of the electrode 1, and as shown in FIGS. 1 (b) and 2 (b), the outer peripheral portion of the electrode 1 is sandwiched between two pairs of sandwiching members 4 (recesses 7). Be caught in. When the electrode 1 at an appropriate position is housed in the recess 7 of the sandwiching member 4, the sandwiching member 4 and the electrode 1 do not abut, so that each pair of sandwiching members 4 is in the predetermined closed state at that time. The determination electrodes 8 provided on each pair of sandwiching members 4 come into contact with each other. Therefore, if the determination electrodes 8 are in an energized state, it is determined that each pair of sandwiching members 4 is in a predetermined closed state, and based on this, each electrode 1 is in a predetermined position in the electrode radial direction.

On the other hand, if, for example, the electrode 1 is displaced above FIG. 3 (a) with respect to the electrode 1 at an appropriate position shown by the alternate long and short dash line in FIG. Since the position is fixed, when each pair of sandwiching members 4 is closed from the open state of FIG. 2A, the sandwiching member 4 on the upper side of FIG. 3A is placed on the upper side surface of the electrode 1 in the drawing. The sandwiching members 4 that are in contact with each other and form a pair are not closed any more. That is, the predetermined closed state is not reached. Unless the pair of sandwiching members 4 are in a predetermined closed state in this way, the determination electrodes 8 do not abut with each other, and therefore the determination electrodes 8 are in a non-energized state. Therefore, it is determined that any of the electrodes 1 is misaligned if the determination electrodes 8 are in a non-energized state even though the sandwiching member 4 paired with the electrode 1 is sandwiched. can. Similarly, if, for example, the electrode 1 is displaced to the right of FIG. 3 (b) with respect to the electrode 1 at an appropriate position shown by the alternate long and short dash line in FIG. 3 (b), the tip of the sandwiching member 4 is displaced. It comes into contact with the left side surface of the outer peripheral portion of the electrode 1 in the drawing, and the pairing sandwiching member 4 does not close any more, so that the predetermined closed state is not achieved. Unless the pair of sandwiching members 4 are in a predetermined closed state in this way, the determination electrodes 8 do not abut with each other, and therefore the determination electrodes 8 are in a non-energized state. Therefore, it is determined that any of the electrodes 1 is misaligned if the determination electrodes 8 are in a non-energized state even though the sandwiching member 4 paired with the electrode 1 is sandwiched. can. When the misalignment of any of the electrodes 1 is determined in this way and the misalignment is notified, which electrode 1 is positioned in which direction by observing the contact state between the electrode 1 and the sandwiching member 4. It is possible to determine whether or not there is a deviation. Therefore, after that, the operator can correct the electrode position and return to the normal resistance welding operation.

As described above, the operation control and the electrode position deviation determination of the electrode position deviation detecting device 2 of this embodiment are performed by the control device 3. The control device 3 is configured by incorporating a computer system for performing arithmetic processing, and includes not only an arithmetic processing apparatus having an advanced arithmetic processing function, but also a storage device for storing programs and data, various sensors, and an external device. It is configured with an input / output device that controls input / output. FIG. 4 is a flowchart showing an operation and a calculation process for determination of the electrode position deviation detecting device 2 executed by the control device 3. This arithmetic processing is started in a state where the resistance welding device (counter electrode 1) is fixed at the predetermined determination position, and first, in step S1, the sandwiching member 4 of each pair is moved to the outer peripheral portion side of each electrode 1. And sandwich each electrode 1.

Next, the process proceeds to step S2, and a current is applied between the determination electrodes 8.

Next, the process proceeds to step S3 to determine whether or not the determination electrodes 8 are in a non-energized state. If the determination electrodes 8 are in a non-energized state, the process proceeds to step S4, and if not, the process proceeds to step S4. Goes to step S6.

In step S4, the process proceeds to step S5 after it is determined that one of the electrodes 1 is misaligned because each pair of sandwiching members 4 is not in a predetermined closed state.

In step S5, the process is terminated after notifying the electrode position deviation by a notification means (not shown). Examples of the notification means include a display, a signal lamp, a buzzer, and the like.

On the other hand, in step S6, the resistance welding device is instructed to return to the normal position and then returns.

According to this arithmetic processing, when the resistance welding device (counter electrode 1) is moved and fixed at a predetermined determination position, each pair of sandwiching members 4 is moved to the outer peripheral portion side of each electrode 1 and sandwiched. In this state, the determination electrode 8 is energized. At this time, if the determination electrodes 8 are in an energized state, each pair of sandwiching members 4 is in a predetermined closed state, so that each electrode 1 is in an appropriate position, and therefore the electrode 1 is not displaced, so that resistance welding is performed. The device can be returned to the normal position, for example, to continue mass production vehicle body manufacturing. On the other hand, if the determination electrodes 8 are in a non-energized state, it can be determined that the electrodes 1 are misaligned because the sandwiching members 4 of each pair are not in the predetermined closed state and therefore the electrodes 1 are not in the proper positions. .. Then, when the electrode position deviation is determined, the electrode position deviation is notified by, for example, a display, a signal lamp, a buzzer, or the like. When the electrode misalignment is notified, for example, the operator can correct the misalignment of the electrode 1 and return to the normal resistance welding work. This makes it possible to secure and improve the resistance welding quality. That is, steps S3 and S4 of the arithmetic processing of FIG. 4 executed by the control device 3 constitute the signal generating means, the determination electrode current applying means, the non-energized detecting means, the non-closed state detecting means, and the misalignment determining means of the present invention. do.

The electrode position deviation detecting device 2 of this embodiment can be configured as the following modification. For example, the advancing / retreating device 13 includes an electric motor, a ball screw attached to the rotating shaft thereof, and a ball screw nut screwed to the ball screw, and is moved in the extension direction of the ball screw by the thrust of the screw. When the rod member 14 is attached to the ball screw nut to be configured, the sandwiching member 4 is brought into contact with the outer peripheral portion of the electrode 1 when the sandwiching member 4 is closed, and the sandwiching member 4 is further subjected to. When it becomes impossible to move, the movement of the ball screw nut is also stopped at that point, and the rotation of the ball screw is also stopped at that point. Therefore, for example, when the rotation amount of the electric motor rotating the ball screw is detected by an encoder or the like and the rotation amount stops before the rotation amount of the sandwiching member 4 in a predetermined closed state, the sandwiching member 4 May be determined to be in contact with the outer peripheral portion of the electrode 1 and it may be determined that any of the opposing electrodes 1 is misaligned.

As described above, in the electrode position deviation detecting device 2 of the resistance welding device of this embodiment, for example, the resistance welding device (counter electrode 1) attached to the manipulator of the industrial robot faces each other in a predetermined position. The sandwiching member 4 simultaneously moved to the outer peripheral side of each electrode so as to sandwich both of the electrodes 1 is not in a predetermined closed state, that is, the sandwiching member 4 is not completely closed due to the misalignment of the electrode 1. Therefore, it can be determined that any of the electrodes 1 is misaligned, and thereby any misalignment of the two opposing electrodes 1 can be detected.

Further, since the determination electrode 8 to be abutted in the predetermined closed state of the sandwiching member 4 is in the non-energized state, it is determined that the sandwiching member 4 is not in the predetermined closed state, that is, it is not completely closed due to the misalignment of the electrode 1. This makes it possible to reliably detect the misalignment of the two electrodes 1 facing each other.

FIG. 5 is a schematic configuration diagram showing a main part of the second embodiment of the electrode position deviation detecting device 2 of the present invention. In the electrode position deviation detecting device 2 of this embodiment, in a state where the resistance welding device (counter electrode 1) is moved and fixed to the predetermined determination position, the outer peripheral portion or the tip portion of each electrode 1 is radially outside. It is configured to include a plurality of electrode distance sensors located. This electrode distance sensor is a sensor capable of non-contactly detecting the distance to the outer peripheral portion or the tip portion of the electrode 1, and in this embodiment, it is composed of a proximity switch 5. As is well known, the proximity switch 5 is a sensor that forms a magnetic field around a coil, detects changes in inductance and loss due to the approach of metal to the magnetic field, and outputs a signal, for example, a metal is predetermined. An on signal is output when the distance is less than the distance. That is, the predetermined distance is the distance until the detection signal of the proximity switch 5 is turned on. In FIG. 5, a plurality of (12 in the figure) proximity switches 5 are equally arranged toward the electrode 1 on the radial outer side of the outer peripheral portion or the tip portion of the electrode 1 moved / fixed to the predetermined determination position. The output signal is read by the control device 3. At that time, the distance in the electrode radial direction to each proximity switch 5 with respect to the outer peripheral portion or the tip portion of the electrode 1 at an appropriate position is the above-mentioned predetermined distance, that is, the distance at which the proximity switch 5 is turned on and the predetermined gap in FIG. Equivalent to the added value of. On the other hand, if the electrode 1 is displaced in the radial direction by, for example, a distance equivalent to or more than the predetermined gap in FIG. 1, an on signal is output from any of the proximity switches 5, so that the on signal of the proximity switch 5 is used. , Which electrode 1 is displaced in which direction can be detected and determined.

Like the control device 3 of the first embodiment, the control device 3 of this embodiment is configured by incorporating a computer system for performing arithmetic processing, and is only an arithmetic processing apparatus having an advanced arithmetic processing function. Instead, it is equipped with a storage device that stores programs and data, and an input / output device that controls input / output with various sensors and external devices. FIG. 6 is a flowchart showing an operation and a calculation process for determination of the electrode position deviation detecting device 2 executed by the control device 3. This arithmetic processing is started in a state where the resistance welding device (counter electrode 1) is fixed at the predetermined determination position, and first, in step S11, the detection signals of the respective proximity switches 5 are read.

Next, the process proceeds to step S12, and it is determined whether or not the distance to the electrode 1 (the outer peripheral portion or the tip portion thereof) is equal to or less than a predetermined distance, that is, whether or not the detection signal of the proximity switch 5 is an on signal. If the detection signal of the proximity switch 5 is an on signal, that is, the distance to the electrode 1 (the outer peripheral portion or the tip portion thereof) is not more than a predetermined distance, the process proceeds to step S13, and if not, the process proceeds to step S15. Transition.

In step S13, the process proceeds to step S14 after determining that any of the electrodes 1 whose distance (to the outer peripheral portion or the tip portion) is equal to or less than a predetermined distance is misaligned.

In step S14, the process is terminated after notifying the electrode position deviation by a notification means (not shown). Examples of the notification means include a display, a signal lamp, a buzzer, and the like.

On the other hand, in step S15, the resistance welding device is instructed to return to the normal position and then returns.

According to this arithmetic processing, when the resistance welding device (counter electrode 1) is moved / fixed to a predetermined determination position, the detection signal of each proximity switch 5 is read. At this time, if the detection signals of all the proximity switches 5 are off signals, the outer peripheral portion or the tip portion of the electrode 1 is separated from the proximity switch 5 by a predetermined distance or more, so that each electrode 1 is in an appropriate position. Since the electrode 1 is not misaligned, the resistance welding apparatus can be returned to the normal position, and for example, mass production of the vehicle body can be continued. On the other hand, if the detection signal of any of the proximity switches 5 is an on signal, the distance between the outer peripheral portion or the tip end portion of the corresponding electrode 1 and the proximity switch 5 outputting the on signal is a predetermined distance or less, and therefore each. Since the electrode 1 is not in the proper position, it can be determined that the electrode 1 is misaligned. Then, when the electrode position deviation is determined, the electrode position deviation is notified by, for example, a display, a signal lamp, a buzzer, or the like. When the electrode misalignment is notified, for example, the operator can correct the misalignment of the electrode 1 and return to the normal resistance welding work. This makes it possible to secure and improve the resistance welding quality. That is, steps S12 and S13 of the arithmetic processing of FIG. 6 executed by the control device 3 constitute the positional deviation determination means of the present invention.

When the proximity switch 5 is positioned radially outside the outer peripheral portion or the tip portion of the electrode 1 in the electrode position deviation detecting device 2 of FIG. 5, for example, the plurality of proximity switches 5 shown in the figure are separated from the electrode 1. The electrode 1 is retracted in the radial direction of the electrode, the electrode 1 is moved / fixed to the position shown in the figure (predetermined determination position), and then the proximity switch 5 is advanced in the radial direction of the electrode to move the outer peripheral portion or the tip portion of the electrode 1. It is also possible to approach the outside in the radial direction of. However, for example, the proximity switch 5 is fixed at the position shown in the figure, and two electrodes 1 having a wide distance in the opposite direction are brought close to each other at the center position of the plurality of proximity switches 5, whereby the plurality of proximity switches 5 are electrodes. It is realistic to operate the robot and the resistance welding device so as to be located on the radial outer side of the outer peripheral portion or the tip portion of 1.

FIG. 7 is a modification of the electrode misalignment detection device 2 of FIG. 5, and in the electrode misalignment detection device 2 of FIG. 5, a plurality of proximity switches 5 are evenly distributed on the outer peripheral portion or the tip end portion of the electrode 1 in the radial direction. On the other hand, in FIG. 7, a single ring-shaped proximity switch 5 is located radially outside the outer peripheral portion or the tip portion of the electrode 1. This ring-shaped proximity switch 5 outputs, for example, an on-signal when the distance between the inner circumference of the proximity switch 5 and the outer peripheral portion or the tip portion of the electrode 1 is equal to or less than a predetermined distance. The misalignment of the electrode 1 can be detected in the same manner as in the arithmetic processing of 6. In the electrode position deviation detecting device 2 of FIG. 7, it is not possible to determine in which direction the electrode 1 is displaced only by the detection signal of the proximity switch 5. Further, in the electrode position deviation detecting device 2 of FIG. 7, the electrodes 1 are moved to a predetermined determination position by moving the electrodes 1 having widened intervals in the opposite direction to the internal position of the ring-shaped proximity switch 5 and bringing them close to each other.・ Fix.

As described above, in the electrode position deviation detecting device 2 of the resistance welding device of this embodiment, for example, the resistance welding device (counter electrode 1) attached to the manipulator of the industrial robot faces each other in a predetermined position. A proximity switch 5 (electrode distance sensor) that is simultaneously close to the outer peripheral portion or the tip portion of both of the electrodes 1 and is located on the radial outer side of each electrode 1 is in a non-contact state with the distance in the electrode radial direction to each electrode 1. When the distance in the radial direction of the electrode to each of the detected electrodes 1 is equal to or less than a predetermined distance, it can be determined that the electrode 1 is misaligned. Any misalignment can be detected.

FIG. 8 is a cross-sectional view seen from the electrode radial direction showing a further modification of the electrode position deviation detecting device 2 of FIG. 5, and the outline of the arrangement of the proximity switch 5 (electrode distance sensor) seen from the electrode extension direction is as follows. It is the same as FIG. In this electrode position deviation detecting device 2, the proximity switch 5 is located radially outside the tip of each electrode 1, and an electrode position reflecting member 6 is interposed between the proximity switch 5 and the tip of each electrode 1. It is dressed up. The electrode position reflecting member 6 is formed of, for example, a circular metal plate having a predetermined thickness in the electrode extension direction, and the proximity switch 5 is arranged to face the outer peripheral surface of the electrode position reflecting member 6. The electrode position reflecting member 6 is slidably arranged between two support plates 15 separated by a predetermined dimension in the electrode extension direction, and is placed at the tip of the electrode 1 at an appropriate position by a spring member (not shown). It is moved back to the opposite position. The proximity switch 5 is embedded in a space holding wall portion 16 fixed between two support plates 15 on the radial outer side of the electrode position reflecting member 6. The electrode position reflecting member 6 is provided with a recessed portion (hole portion) 17 having a truncated cone-shaped cross section that is tapered in the direction of extension of the electrode at the center of the plate surface facing the tip of each electrode 1. The tip end portion of the electrode 1 moved / fixed to the predetermined determination position is inserted into the recessed portion 17. Since the tips of the electrodes 1 of this embodiment are all hemispherical, when the tips of the hemisphere are inserted into the recesses 17 having a tapered cross-section conical trapezoidal shape, the tips of the electrodes 1 are positioned at the tips. Accordingly, the electrode position reflecting member 6 is moved in the electrode radial direction. In the figure, the upper electrode 1 is in the proper position, while the lower electrode 1 is displaced to the right in the radial direction. The proximity switch 5 outputs an on signal when the distance to the outer peripheral portion of the electrode position reflecting member 6 moved in the electrode radial direction according to the position of the tip portion of each electrode 1 becomes a predetermined distance or less. do. Therefore, the electrode misalignment detecting device 2 can detect the misalignment of the electrode 1 in the same manner as the above-mentioned arithmetic processing of FIG.

As described above, in the electrode position deviation detecting device 2 of the resistance welding apparatus of this embodiment, for example, when the tip portion of the electrode 1 has such a hemispherical shape or a tapered shape, the electrode up to the tip portion thereof is formed. Although it is difficult to detect the radial distance, the proximity switch 5 (electrode distance sensor) measures the radial distance to the outer peripheral portion of the electrode position reflecting member 6 that reflects the position of the tip portion by moving in the electrode radial direction. It can be detected relatively easily, and the configuration of the electrode position deviation detecting means can be shortened in the electrode extension direction as compared with the case where the distance in the electrode radial direction to the outer peripheral portion of the electrode 1 is detected. ..

Next, a third embodiment of the electrode position deviation detecting device 2 of the present invention will be described. The electrode position deviation detecting device 2 of this embodiment is a modification of the above-mentioned first embodiment. FIG. 9 is a partial cross-sectional plan view showing a main part of the electrode position deviation detecting device 2 of this embodiment, and FIG. 9A shows a state in which the sandwiching member 4 is open, FIG. 9B. ) Indicates a state in which the sandwiching member 4 is closed. Since the electrode misalignment detection device 2 of this embodiment is similar to the electrode misalignment detection device 2 of the first embodiment, the equivalent configurations are designated by the same reference numerals and detailed description thereof will be given. Is omitted. In this embodiment, the sandwiching member 4 is stretched in the direction opposite to the rotation shaft 11 side, and a movable determination electrode 21 is added to the stretched portion 4a. In order to distinguish the movable type determination electrode 21 from the above-mentioned fixed type determination electrode 8, the latter (fixed type) is defined as the first determination electrode 8 and the former (movable type) is defined as the second determination electrode 21. The configuration on the base end portion side of the sandwiching member with respect to the first determination electrode 8 is the same as that of the first embodiment.

The stretched portion 4a of the sandwiching member 4 is stretched so as to spread in the sandwiching member opening direction from the mounting portion of the first determination electrode 8, and is formed in the through hole formed in the stretching portion 4a in the sandwiching member opening / closing direction. The shaft portion of the second determination electrode 21 is inserted, and a large-diameter portion for preventing disconnection is provided at the end portion of the shaft portion on the opening direction side of the sandwiching member. A hemispherical electrode portion is provided at the tip portion of the shaft portion of the second determination electrode 21 in the closing direction in the closing direction, and a coil spring 22 surrounds the shaft portion between the electrode portion and the extension portion 4a. It is assisted to do. Therefore, the second determination electrode 21 is urged by the coil spring 22 so that the electrode portion protrudes from the extending portion 4a in the closing direction of the sandwiching member, and slides in the through hole when a force is applied in the opening direction of the sandwiching member. do. Similar to the first determination electrode 8, a current for determining energization is applied to the second determination electrode 21 from the control device 3.

The position of the protruding tip portion of the electrode portion of the second determination electrode 21 urged by the coil spring 22 is set to a position protruding by a predetermined dimension from the protruding tip portion of the first determination electrode 8. That is, when the opposing sandwiching members 4 are closed, the second determination electrode 21 abuts twice as fast as the predetermined dimension before the first determination electrodes 8 abut on each other. This means that the second determination electrodes 21 are in contact with each other even if the sandwiching members 4 facing each other are located far from each other. Further, when the sandwiching members 4 can be further closed after the second determination electrodes 21 are in contact with each other, the second determination electrode 21 slides in the sandwiching member opening direction along the through hole. The protrusion dimension of the electrode portion of the second determination electrode 21 with respect to the first determination electrode 8 can be changed by adjusting the position of the large diameter portion provided at the end portion of the shaft portion. The position of the large diameter portion can be adjusted, for example, by forming the large diameter portion with a so-called double nut. Further, as shown in FIG. 9B, a predetermined gap (hereinafter referred to as a predetermined gap) is formed between the recess 7 of the sandwiching member 4 in the closed state and the electrode 1 at the normal position. ing. That is, when considering the opening / closing direction of the sandwiching member, the first determination electrodes 8 are in contact with each other when the sandwiching member 4 is closed, even if the electrodes 1 are displaced within the predetermined gap range. In this embodiment, when the electrode 1 is present within this predetermined range, it is defined that the electrode 1 is in an appropriate position.

On the other hand, when the amount of misalignment of the electrode 1 exceeds the predetermined gap between the electrode 1 at the normal position and the recess 7, the first determination electrodes 8 do not come into contact with each other as shown in FIG. 10A. However, when the amount of misalignment is within the addition value of the protrusion dimension of the electrode portion of the second determination electrode 21 with respect to the protrusion tip portion of the first determination electrode 8 and the predetermined gap, the second determination electrode 21 They come into contact with each other. Further, when the amount of misalignment of the electrode 1 exceeds the addition value of the predetermined gap of the recess 7 with respect to the electrode 1 at the normal position and the protrusion dimension of the electrode portion of the second determination electrode 21 with respect to the protruding tip portion of the first determination electrode 8. As shown in FIG. 10B, not only the first determination electrodes 8 but also the second determination electrodes 21 do not come into contact with each other. In this embodiment, as in the first embodiment, the determination current is applied between the first determination electrode 8 and the second determination electrode 21, and the first determination electrode 8 is in a non-energized state. However, when the second determination electrode 21 is in an energized state, it is assumed that the electrode 1 is displaced within the permissible range and the corresponding resistance welding process is not stopped.

FIG. 11 is a flowchart showing an operation and a determination process for the electrode position deviation detecting device 2 of this embodiment, which is executed by the control device 3. This arithmetic processing is started in a state where the resistance welding device (counter electrode 1) is fixed at the predetermined determination position, and first, in step S21, the sandwiching member 4 of each pair is moved to the outer peripheral portion side of each electrode 1. And sandwich each electrode 1.

Next, the process proceeds to step S22, and a current is applied between the first determination electrode 8 and the second determination electrode 21.

Next, the process proceeds to step S23 to determine whether or not the first determination electrode 8 is in the non-energized state, and if the first determination electrode 8 is in the non-energized state, the process proceeds to step S24. If not, the process proceeds to step S26.

In step S24, it is determined whether or not the second determination electrode 21 is in the non-energized state, and if the second determination electrode 21 is in the non-energized state, the process proceeds to step S27, and if not, the step is performed. Move to S25.

In step S25, a warning is given on the assumption that any of the electrodes 1 is misaligned within the permissible range, and then the process proceeds to step S26. For this warning notification, for example, a display, a signal lamp, a buzzer, or the like is used.

In step S26, the resistance welding apparatus is instructed to return to the normal position and then returns.

On the other hand, in step S27, it is determined that the sandwiching member 4 of each pair is not in the predetermined closed state and one of the electrodes 1 is misaligned (in this case, exceeding the allowable range), and then the process proceeds to step S28. do.

In step S28, the process is terminated after notifying the electrode position deviation by a notification means (not shown). Examples of the notification means include a display, a signal lamp, a buzzer, and the like. That is, in this case, since the resistance welding apparatus does not return, the corresponding resistance welding process is stopped.

According to this arithmetic processing, as in the first embodiment, if the first determination electrodes 8 are in an energized state, each electrode 1 is in an appropriate position, and therefore the electrode 1 is not misaligned. The resistance welding device can be returned to the normal position, and for example, mass production of the vehicle body can be continued. On the other hand, if both the first determination electrode 8 and the second determination electrode 21 are in a non-energized state, it can be determined that the sandwiching member 4 of each pair is not in the predetermined closed state, and therefore the electrode 1 is misaligned. .. Then, when the electrode position deviation is determined, the electrode position deviation is notified by, for example, a display, a signal lamp, a buzzer, or the like. When the electrode misalignment is notified, the corresponding resistance welding process is stopped, so that, for example, the operator can correct the misalignment of the electrode 1 and return to the normal resistance welding operation. This makes it possible to secure and improve the resistance welding quality. That is, steps S23, S24, and S27 of the arithmetic processing of FIG. 4 executed by the control device 3 are the signal generating means, the determination electrode current applying means, the non-energized detecting means, the non-closed state detecting means, and the misalignment determining means of the present invention. To configure. On the other hand, if the first determination electrodes 8 are not energized but the second determination electrodes 21 are energized, the electrodes 1 are not in the proper positions and are misaligned. Assuming that the amount of misalignment is within the permissible range, the electrode misalignment is warned by, for example, a display, a signal lamp, or a buzzer. In this case, the resistance welding device can be returned to the normal position and mass production of the vehicle body can be continued. When the electrode position deviation is warned, for example, the electrode 1 can be returned to the proper position by correcting the electrode position at the next stop of operation.

Although the electrode position deviation detecting device 2 of the resistance welding device according to the embodiment has been described above, the present invention is not limited to the configuration described in the above embodiment, and is within the scope of the gist of the present invention. Various changes are possible. For example, in the first embodiment described above, the sandwiching members facing each other rotate around the rotation axis and are moved from both outer sides in the radial direction so as to sandwich each electrode 1. However, this sandwiching is performed. The electrode sandwiching configuration by the member may be another configuration. For example, by engaging racks on both radial sides of a pinion mounted on the rotating shaft of one electric motor and attaching one sandwiching member to each of the racks, two sandwiching members can be electrodeed from both sides in the radial direction of the electrodes. Since the electrode 1 can be moved closer to or farther from 1, the electrode 1 can be sandwiched from the diameter direction by the sandwiching member by this configuration.

Further, as the electrode distance sensor that detects the distance in the radial direction of the electrode to the electrode, a non-contact type distance sensor that uses ultrasonic waves, infrared rays, laser light, or the like can also be used.

Further, in the third embodiment, instead of the coil spring 22 that movably supports the second determination electrode 21 in the opening / closing direction of the sandwiching member, a leaf spring member that bends in the opening / closing direction of the sandwiching member 4 is inserted in the sandwiching member. The second determination electrode 21 (the electrode portion) may be rigidly attached to the tip portion of the leaf spring member. In this case, the protrusion dimension of the second determination electrode 21 (the electrode portion) attached to the leaf spring member with respect to the first determination electrode 8 is set to be the same as that of the third embodiment. Actions and effects can be obtained.

Further, instead of the second determination electrode 21 itself in the third embodiment, a load sensor such as a strain gauge can be used. In this case, for example, leaf spring members that come into contact with each other at the same timing as the second determination electrode 21 are provided on each of the sandwiching members 4, and a load sensor is attached to at least one of the leaf spring members. Even if the (first) determination electrodes 8 are in a non-energized state, if the load detected by the load sensor is equal to or greater than the threshold value, the electrodes 1 are misaligned, but the amount of misalignment is permissible. Warn that it is within range. At the time of the electrode misalignment warning, for example, the electrode position is corrected and the electrode 1 is returned to the proper position at the time of the next operation stop. Further, if the determination electrode 8 is in a non-energized state and the detected load is less than the threshold value and the operation is stopped because the amount of misalignment of the electrode 1 exceeds the allowable range, it is equivalent to the third embodiment. The action and effect of can be obtained. When a piezo element is used for the load sensor, for example, it is conceivable to attach the load sensor to the seat surface of the coil spring 22 of the third embodiment.

Further, instead of this load sensor, it is also possible to use a non-contact type distance sensor as used in the second embodiment. In this case, for example, a non-contact type distance sensor is provided on one of the stretched portions 4a of the sandwiching member 4, and a distance detection target member that can be detected by the non-contact type distance sensor is provided on the other. For example, if the non-contact type distance sensor is the proximity switch 5, a metal member with which the proximity switch 5 reacts is attached to the stretched portion 4a at the opposite position. Even if the (first) determination electrodes 8 are in a non-energized state, if the distance detected by the distance sensor is less than the threshold value, the electrodes 1 are misaligned, but the amount of misalignment is permissible. Warn that it is within range. At the time of the electrode misalignment warning, for example, the electrode position is corrected and the electrode 1 is returned to the proper position at the time of the next operation stop. Further, if the determination electrode 8 is in a non-energized state and the detection distance is equal to or greater than the threshold value and the operation is stopped because the amount of misalignment of the electrode 1 exceeds the allowable range, it is equivalent to the third embodiment. The action and effect of can be obtained.

1 Electrode (resistance welding equipment)
2 Electrode misalignment detection device 3 Control device 4 Sandwiching member 5 Proximity switch (electrode distance sensor)
6 Electrode position reflection member 8 Judgment electrode (1st judgment electrode)
21 Second judgment electrode

Claims (4)

In a resistance welding device that joins multiple members to be joined by sandwiching them between facing electrodes and applying pressure to them.
The resistance welding device is provided with an electrode misalignment detecting means for detecting the misalignment of the outer peripheral portion of each electrode by being approached at the same time as the outer peripheral portions of both of the facing electrodes in a predetermined position.
The electrode position deviation detecting means is
With the resistance welding device in the predetermined position, the electrodes are moved to the outer peripheral portions of both of the electrodes so as to sandwich the electrodes from both outer sides in the radial direction of the opposing electrodes, and the electrodes are in the proper positions. With the sandwiching member that is in a predetermined closed state in some cases,
A signal generation means for outputting a movement state signal according to the movement state of the sandwiching member toward the outer peripheral portion of the electrode, and
A non-closed state detecting means for detecting that the sandwiching member moved to the outer peripheral side of the electrode is not in the predetermined closed state based on the moving state signal of the signal generating means.
The non-closed state detecting means is provided with a misalignment determining means for determining that any of the electrodes is misaligned when the sandwiching member is detected to be in a state other than the predetermined closed state. Electrode position deviation detection device for resistance welding equipment. The signal generating means is
A determination electrode provided on the sandwiching member and moved to the outer peripheral side of the electrode and abutting against each other when the sandwiching member is in the predetermined closed state.
A determination electrode current applying means for applying a current between the determination electrodes in a state where the sandwiching member is moved to the outer peripheral portion side of the electrode is provided.
The non-closed state detecting means
A non-energized detecting means for detecting that the determination electrodes are in a non-energized state while a current is applied between the determination electrodes by the determination electrode current applying means is provided.
The electrode position of the resistance welding apparatus according to claim 1, wherein the non-energized detecting means determines that the sandwiching member is not in a predetermined closed state when the determination electrodes are in a non-energized state. Misalignment detector. In a resistance welding device that joins multiple members to be joined by sandwiching them between facing electrodes and applying pressure to them.
The resistance welding device is provided with an electrode misalignment detecting means for detecting the misalignment of the outer peripheral portion or the tip portion of each electrode by being approached at the same time as the outer peripheral portion or the tip portion of both of the facing electrodes in a predetermined position.
The electrode position deviation detecting means is
An electrode distance sensor that detects the radial distance of each electrode to the outer peripheral portion or the tip portion of each electrode in a non-contact state, with the resistance welding device located on the radial outer side of the facing electrode in the predetermined position. ,
It is characterized by comprising a misalignment determining means for determining that the electrode is misaligned when the distance in the electrode radial direction to the electrode detected by the electrode distance sensor is equal to or less than a predetermined distance. Electrode misalignment detection device for resistance welding equipment. When the electrode distance sensor detects the distance in the electrode radial direction to the tip of each electrode, it is arranged between the tip and the electrode distance sensor, and the diameter of the electrode depends on the position of the tip. Equipped with an electrode position reflection member that moves in the direction
The resistance according to claim 3, wherein the electrode distance sensor detects the distance in the radial direction of the electrode to the tip of the electrode by detecting the distance in the radial direction of the electrode to the electrode position reflecting member. Electrode misalignment detection device for welding equipment.

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