Abstract: A gripping device constituting a welding device has a first contactor and a second contactor, which face each other and come in contact with a material to be welded. The first contactor vibrates at a predetermined vibration frequency under the effect of a first vibrator. The second contactor may be configured so as to be vibrated by a second vibrator. In this case, it is preferable that the first contactor and the second contactor are vibrated at different vibrational frequencies. In the abovementioned configuration, the first contactor and the second contactor periodically repeat contact with and separation from the material to be welded. In this state, the gripping device moves in the welding direction and welding is carried out on the material to be welded.

Abstract: A resistance welding device is provided with a lower tip and an upper tip that serve as welding tips, and pressing rods that serve as pressing members. The upper tip and the pressing rods press a stacked body, which is to be welded, from the metallic plate side, which is the outermost member of the stacked body. The lower tip presses the stacked body from the lowermost metallic plate side. In this state, and electric current is conducted from the upper tip to the lower tip.

Abstract: A resistance welding method for welding a stack of three or more workpieces. The method includes the steps of holding a first welding tip in abutment against a first outermost workpiece, holding a second welding tip in abutment against a second outermost workpiece, and holding a pressing member in abutment against the first outermost workpiece. The method also includes the steps of gripping the stacked assembly with the first welding tip, the second welding tip, and the pressing member and passing an electric current between the first welding electrode and the second welding electrode.

Abstract: High precision work is performed on a work target (workpiece) during conveyance, irrespective of the oscillations accompanying conveyance. A work method includes steps of: predicting a predicted oscillation pattern occurring in a workpiece (W) afterwards from the measurement results of oscillation occurring in the workpiece (W) during conveyance by way of a workpiece conveyance device (2); controlling a robot (131) so as to operate at an oscillation according to the predicted oscillation pattern thus predicted; detecting oscillation occurring in the robot (131) during the step of controlling; and comparing the oscillation occurring in the robot (131) with the predicted oscillation pattern, and in the case of differing, adjusting so that the oscillation of the robot (131) matches the predicted oscillation pattern, in which each of these steps is completed before the robot (131) performs work on the workpiece (W).

Abstract: High precision work is performed on a work target (workpiece) during conveyance, irrespective of the oscillations accompanying conveyance. A work method includes steps of: predicting a predicted oscillation pattern occurring in a workpiece (W) afterwards from the measurement results of oscillation occurring in the workpiece (W) during conveyance by way of a workpiece conveyance device (2); controlling a robot (131) so as to operate at an oscillation according to the predicted oscillation pattern thus predicted; detecting oscillation occurring in the robot (131) during the step of controlling; and comparing the oscillation occurring in the robot (131) with the predicted oscillation pattern, and in the case of differing, adjusting so that the oscillation of the robot (131) matches the predicted oscillation pattern, in which each of these steps is completed before the robot (131) performs work on the workpiece (W).

Abstract: A resistance welding device is provided with a lower tip and an upper tip that serve as welding tips, and pressing rods that serve as pressing members. The upper tip and the pressing rods press a stacked body, which is to be welded, from the metallic plate side, which is the outermost member of the stacked body. The lower tip presses the stacked body from the lowermost metallic plate side. In this state, and electric current is conducted from the upper tip to the lower tip.

Abstract: The intensity of first reflected ultrasonic waves reflected from an end of a first electrode tip is measured while the electrode tip is separated from a workpiece. The intensity of second reflected waves reflected from the end of the electrode tip is measured while the electrode tip contacts with the workpiece. Based on the above intensities, an intensity ratio (reflectance) and the fraction of the waves entering the workpiece are determined from the following equations: reflectance=(intensity of second reflected waves)/(intensity of first reflected waves) fraction of waves entering the workpiece=1?reflectance. From a predetermined correlative relationship between a contact area of a region enabling ultrasonic waves to be incident on the workpiece and the determined fraction of the entering waves, a ratio (contact area ratio) is determined between a total area of the region and a contact area of the region contacting with the workpiece.

Abstract: Disclosed are a resistance welding method for welding a stack of three or more works and a device therefor. A stack is formed in such that the thinnest work having the smallest thickness among the works is placed in the outermost position. The stack is held between a first welding electrode and a second welding electrode. A pressing member is brought into contact with a location of the thinnest work different from the location with which the first welding electrode is in contact, and the pressing member is caused to press the stack from the thinnest work side. In a state that the pressing force exerted on the stack by the first welding electrode and the pressing member is balanced with the pressing force exerted on the stack by the second welding electrode, current is applied between the first welding electrode and the second welding electrode.

Abstract: A vehicle wheel alignment measuring method and apparatus capable of measuring wheel alignment of a vehicle body with high accuracy without wheels mounted in an assembly line. A dummy wheel (10) is mounted on a wheel mounting portion (6) on which a wheel is not mounted. Subsequently, with a vehicle body supported, a wheel mounting portion elevating means (8) elevates the wheel mounting portion (6) via the dummy wheel (10). Thereafter, an alignment measuring means (9) measures wheel alignment for the wheel mounting portion (6) on which the dummy wheel (10) is mounted.

Abstract: For spot-welding a plurality of metal workpieces, the metal workpieces are gripped and pressed under a pressing force by a pair of electrode tips, thereby forming a contact interface between the metal workpieces. Then, an electric current is passed between the electrode tips, and it is determined whether the contact interface is melted or not. Simultaneously when it is judged that the contact interface is melted, the pressing force applied from the electrode tips to the metal workpieces is reduced to such a level that the electrode tips and the metal workpieces are kept in contact with each other, the metal workpieces are kept in contact with each other, and the electric current keeps flowing between the electrode tips.

Abstract: A resistance welding method, which resistance-welds a pair of workpieces by gripping the workpieces with a pair of electrode tips under a prescribed welding pressure, and supplies a welding current through the electrode tips to the workpieces, includes the steps of detecting a change in an amount of expansion of a nugget produced in the workpieces, along a direction in which the electrode tips grip the workpieces therebetween, determining whether the detected change is smaller than a threshold value or not, and gradually increasing the welding current flowing through the workpieces after the detected change is judged as being smaller than the threshold value.

Abstract: A vehicle wheel alignment measuring method and apparatus capable of measuring wheel alignment of a vehicle body with high accuracy without wheels mounted in an assembly line. A dummy wheel (10) is mounted on a wheel mounting portion (6) on which a wheel is not mounted. Subsequently, with a vehicle body supported, a wheel mounting portion elevating means (8) elevates the wheel mounting portion (6) via the dummy wheel (10). Thereafter, an alignment measuring means (9) measures wheel alignment for the wheel mounting portion (6) on which the dummy wheel (10) is mounted.

Abstract: The intensity of first reflected ultrasonic waves reflected from an end of a first electrode tip is measured while the electrode tip is separated from a workpiece. The intensity of second reflected waves reflected from the end of the electrode tip is measured while the electrode tip contacts with the workpiece. Based on the above intensities, an intensity ratio (reflectance) and the fraction of the waves entering the workpiece are determined from the following equations. reflectance=(intensity of second reflected waves)/(intensity of first reflected waves) fraction of waves entering the workpiece=1?reflectance From a predetermined correlative relationship between a contact area of a region enabling ultrasonic waves to be incident on the workpiece and the determined fraction of the entering waves, a ratio (contact area ratio) is determined between a total area of the region and a contact area of the region contacting with the workpiece.