JP2016016436A - Seam welder or roll spot welder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seam welder or a roll spot welder that can carry out favorable welding by automatically repairing a weld line without coming off an assumed weld line, particularly in a straight line section, has a high versatility, and is adaptable for a variety of work-pieces.SOLUTION: The seam welder or the roll spot welder is a seam welder or a roll spot welder which has at least one disc electrode to carry out the welding of a plurality of stacked work-pieces while rotating the disc electrode, and the seam welder or the roll spot welder comprises a distance detector, the distance detector equipped with means for detecting a distance from a work-piece or the disc electrode, and equipped with means for changing a travel angle of the disc electrode to a direction where the distance comes in a predetermined range value when the distance comes out of a predetermined range value.SELECTED DRAWING: Figure 1

Description

The present invention relates to a seam welder or a roll spot welder that has at least one disk electrode and welds a plurality of stacked workpieces while rotating the disk electrode.

Seam welding or roll spot welding is a welding method in which an overlapped workpiece is sandwiched between upper and lower disk electrodes and resistance welding is performed while rotating the electrodes. These welding methods are frequently used in the manufacturing process of automobile parts and kitchen sinks. For example, automobile frames and kitchen sinks are temporarily attached with flange portions formed by combining a plurality of plates. It is common to perform seam welding while rotating a part between two disk electrodes of a seam welding machine. In some cases, a roll spot welder is used depending on the shape and location of the workpiece. In some cases, there is also a seam welding apparatus having a disk electrode only on one side. In welding, when a workpiece is fixed and a seam welder or a roll spot welder is mounted on an industrial robot or a self-propelled device, welding is performed while moving the disk electrode three-dimensionally, and a seam welder. Alternatively, there is a case where a roll spot welder is fixed and welding is performed while the workpiece is mounted on an industrial robot or a self-propelled device and moved three-dimensionally.

  When welding an automobile frame or a kitchen sink, the copying apparatus may be provided in order to smoothly weld the curved portion because the straight portion and the curved portion are provided. Among these copying apparatuses, the most typical one is a system using a cam (see, for example, Patent Document 1).

  However, when a cam is used, not only the physical burden on the device is large, but also a considerable rigidity is required, and a considerable accuracy is required for the quality of the cam, the configuration may be complicated and expensive. . Furthermore, by providing the cam in the apparatus, the movable range is limited, and the applicable work shape may be limited. Further, when the cam is used, the electrode can be traced in a curved line, but there is substantially no usefulness in welding the straight portion.

  However, even in the welding of the straight portion, there is considerable unevenness in the plate actually used in the straight portion. Furthermore, there are irregularities resulting from the transfer of heat generated during welding. For this reason, the actual flange is not configured as a flange on which ideal flat plates are superimposed. For this reason, when welding is actually performed, the electrode slips due to unevenness on the surface or is fitted in a so-called saddle, and the traveling angle of the disk electrode is forcibly changed, so that the assumed welding line is deviated. In the worst case, derailment may occur. Therefore, an actual weld line does not match an ideal weld line that has been taught to an industrial robot or the like in advance, which causes poor welding and reduced efficiency.

JP 9-31435 A

  Therefore, the present invention can correct a welding line automatically without deviating from an assumed welding line, particularly in a straight portion, and can perform good welding, and can be applied to a wide variety of workpieces. An object is to provide a seam welder or a roll spot welder.

In order to solve the above problems, a seam welder or a roll spot welder according to the present invention has at least one disk electrode, and welds a plurality of stacked workpieces while rotating the disk electrode. A roll spot welder,
The seam welder or roll spot welder is equipped with a distance detector,
The distance detector includes means for detecting the distance to the workpiece or the disk electrode,
When the distance deviates from the predetermined range value, a means for changing the travel angle of the disk electrode in a direction in which the distance falls within the predetermined range value is provided.
Also, it is mounted on seam welders, roll spot welders, or industrial robots with multi-axis workpieces that can be driven in three dimensions, and the travel angle of the disk electrode is changed by the movement or rotation of the industrial robot shaft. It is preferred that
In addition, it is preferable that a slide means capable of approaching and separating the distance detector from the workpiece is provided.
Further, it is preferable that the distance detector detects the distance from the workpiece end.

  That is, in the present invention, a distance detector is provided in the seam welder or the roll spot welder, and the distance from the workpiece is grasped in real time. Then, if the distance between the workpiece and the detector deviates from a certain range value, the traveling angle of the disk electrode is changed on the assumption that it is deviated from the initially assumed welding line by a certain distance. Regarding the distance to the workpiece, for example, in the welding of a straight part with a constant flange depth, the distance between the electrode and the detector is always constant, so it is assumed that it is ideal by detecting the distance from the workpiece end. It is possible to detect a deviation from the weld line. Therefore, it is easy and preferable to measure the distance from the workpiece end. Further, the distance information is detected in real time and sent to the control device, and the traveling angle of the electrode is adjusted based on the information. The predetermined range value is typically set on the basis of a fixed distance to the planned weld line, but is appropriately within a range of several millimeters or 1 mm or less (for example, 0.5 mm) from the initially assumed weld line. It is possible to set.

The travel angle of the disk electrode is changed by changing the angle for holding the electrode and performing a so-called operation of turning the handle. Therefore, it is preferable to provide the electrode holding member with at least one rotation member capable of changing the traveling angle of the electrode on the planar workpiece. Typically, it can be performed by appropriately rotating one or more axes of the industrial robot, and this operation can return the electrode position to a predetermined range value.

The travel angle can be changed by setting it back to a certain angle toward the weld line (in the direction in which the distance falls within the specified range), or detecting and calculating the angle outside the weld line. Various settings can be adopted, such as settings that change accordingly. For example, with respect to the welding line, a constant angle toward the opposite side to the side where the electrode is removed, or an angle that is variable according to the angle that is outside the welding line (the traveling line is at an angle of 30 degrees from the range value line) If it is off, the traveling angle may be changed by, for example, changing the range value line to an angle of 20 degrees inward.

The distance detector uses a limit switch as a contact type detection method, eddy current generated in the metal object to be detected by electromagnetic induction, or captures the change in electrical capacity due to the approach of the detection object, and detects the object to be detected. Light that is output from a proximity sensor that replaces the movement information and presence information of an object with an electrical signal, evaluates and calculates the light emitted from the light source (LED or laser diode) inside the sensor and reflected from the measurement object, and converted to a distance Various distance detectors such as sensors and ultrasonic sensors can be used. In the case of the contact type or the proximity type, it is preferably placed on the holding frame of the electrode so that it is arranged in the vicinity of the disk electrode, and the workpiece end is kept from the nearest distance while keeping the distance from the electrode constant. It can be detected. And by providing a roller at the tip, smooth welding can be maintained even if the detector contacts. In addition, the distance detector is mounted on slide means that can approach and separate from the workpiece, so that the detector position can be appropriately changed according to the depth of the flange of the workpiece. Further, the slide means can also be slid during welding by the control device, so that a corresponding type can be adopted even when the flange depth changes during welding. In this case, by setting in advance the change in the range value of the distance from the workpiece, not only the straight part but also the curved part with variable flange depth can be supported. In the variable portion, the detector can be separated and used together with other known curved portion welding means.

With the above-described configuration of the present invention, it is possible to provide a welder or a roll spot welder that can perform good welding without deviating from an assumed weld line, particularly in a straight portion. In addition, since it can be applied to welding other than straight lines and can be used in combination with other known curved portion welding means, it is highly versatile and can handle a wide variety of workpieces.

It is a figure which shows one example of implementation of this invention It is a figure which shows one example, such as a motion of the welding line of this invention.

  An embodiment of the present invention will be described with reference to the drawings. The seam welder 1 is mounted on an industrial robot (not shown), has a pair of upper and lower disk electrodes 2 and 2 ′, and sandwiches the flange 4 of the upper and lower workpieces 3. The seam welder 1 includes an arm 5, a motor 6, a transformer 7 and the like in addition to the disk electrodes 2 and 2 '. However, these are not different from a known seam welder, and thus the details are omitted. A substantially similar configuration can also be adopted for a roll spot welder. Furthermore, in the case of the present embodiment, an example is shown in which the seam welder 1 is mounted on an industrial robot, but the seam welder is fixed, the workpiece is mounted on the industrial robot, and the workpiece is moved. Embodiments can also be adopted. However, as in the present embodiment, it is preferable to mount the seam welder 1 on an industrial robot from the viewpoint of the operating area and space.

  A distance detector 8 is further provided in the seam welder 1. The distance detector 8 is provided at a position where the distance detector 8 can move along a straight welding line or a workpiece end portion while maintaining a certain distance. In the present embodiment, the distance detector 8 includes a proximity sensor and also includes a slide mechanism 9. A roller 10 is provided at the tip, and can rotate in contact with the work 3. The distance detector 8 captures the distance from the end of the work 3 in real time. When the distance to the workpiece end exceeds a predetermined range value (for example, 0.5 mm) with respect to the initial value, the distance detector 8 sends a message to that effect to a control device (not shown). The control device issues a command to change the running angle and return it to a predetermined range value, and realizes this operation by controlling the support angle of the seam welder or the disk electrode of the industrial robot.

As shown in FIG. 2, the ideal weld line 11 is formed by a straight line at substantially the center of the flange 4. When welding is started, the disk electrodes 2 and 2 'are located at the position of the weld line 11, and the initial value of the distance detector 8 and a predetermined range value 12 are set at this position.
If the actual welding line 13 deviates from the predetermined range value 12 due to unevenness of the surface, the distance detector 8 detects it, and the traveling angle as in the welding line 14 is controlled by the industrial robot. Is changed so as to be within a predetermined range value. In the present invention, since the angle can be changed without interrupting welding, the angle is actually changed with a gentler curve than the drawing. As a specific example of the change of the traveling angle, a means for further detecting the speed or angle deviating from the predetermined range value 12 and appropriately adjusting the angle to be changed according to this angle (for example, α> β It is possible to adopt means for changing the angle. Further, as a result of the change of the traveling angle, when the distance between the distance detector 8 and the end of the work 4 matches the predetermined range value 12, the actual welding line 11 and the position of the assumed welding line 14 match. It is possible to finally match the welding line 11 and the welding line 14 by adopting a configuration in which the traveling angle of 2 and 2 ′ is returned to the initial predetermined set angle.
Further, it may be possible to adopt a means that is lower in cost, such as a means that sets the angle to be changed in advance and repeats as long as the actual welding line 13 is outside the predetermined range value 12 to change the angle, Or, by setting a plurality of predetermined range values 12, the travel angle for returning to the welding line 11 is changed in multiple steps (if the deviated distance is large, the angle is changed more greatly). The following means may be adopted.

DESCRIPTION OF SYMBOLS 1 Seam welding machine 2 Disc electrode 3 Workpiece 4 Flange 5 Arm 6 Motor 7 Transformer 8 Distance detector 9 Slide mechanism 10 Roller 11 Welding line 12 Range value 13 Welding line 14 Welding line

Claims (4)

A seam welding machine or a roll spot welding machine which has at least one disk electrode and welds a plurality of stacked workpieces while rotating the disk electrode,
The seam welder or roll spot welder is equipped with a distance detector,
The distance detector includes means for detecting the distance to the workpiece or the disk electrode,
If the distance is outside the specified range value,
A seam welder or a roll spot welder characterized by comprising means for changing the travel angle of the disk electrode in a direction in which the distance falls within a predetermined range value. It is mounted on a seam welder, a roll spot welder, or an industrial robot that has multiple axes and can be driven three-dimensionally, and the travel angle of the disk electrode is changed by the movement or rotation of the axis of the industrial robot. A seam welder or a roll spot welder according to claim 1   The seam welder or roll spot welder according to claim 1 or 2, wherein a slide means capable of approaching and separating the distance detector from the workpiece is provided.   The seam welder or roll spot welder according to any one of claims 1 to 3, wherein the distance detector detects a distance from the workpiece end.

Images